DE1204704C2 - PROCESS AND EQUIPMENT FOR REDUCING THE INFLUENCE OF INTERFERENCE SIGNALS OVERLAYING A BROADBAND MESSAGE SIGNAL DURING A TRANSMISSION OR A RECORDING AND REPRODUCTION PROCESS - Google Patents

Description

3 4

To achieve the recorded signals, the stretches and actually up to the upper limit frequency

when recording and / or playback of the transferred tape is sufficient and in which the

th amplifier dimensioned so that their frequency characteristic amplitudes of the individual frequencies are reversed

lines complementary to that of the record are proportional to the frequency. The second class

and playback system are. If the empathy of the high-frequency components arises at

sensitivity of the magnetic heads, which detect the signal over the scanning of a part of the image field in which

Transfer to the recording medium and the security is a high level of detail. This can

Signal decrease from the recording medium may be the case, for example, when a

ken, becomes very low, you have to have high reinforcement picket fence, in the latter case that can

just use. ' _t ίο useful signal almost entirely from high frequencies

In all recording and reproducing devices of great amplitude exist. In general

and in all amplifiers there is some noise in such picture details as that mentioned

on. This can be caused by irregularities in the picket fence, against a background, and the highly frequented

Playback medium, of components sequential on its surface, have a relative

stored dust or other imperfections- 15 low amplitude and thus become indistinct,

! guide derive. Most of this noise that a noise signal occurs along with them,

However, it occurs in the amplifiers themselves. This is not the case with useful signals of higher amplitude

/ Amplifier noise contains what is known as disturbance. Also annoying with large areas

standing noise, which increases the noise signal from the thermal movement of almost the same brightness.

arises from within the resistance materials, and 20 more than in areas of the image where pronounced image de-

ne noise that occurs on the statistical tails. In the playback picture there is the

Jiw fluctuations in the emission of electrons caused by snowflakes falling under pressure,

When recording television signals, it is back to the hot cathodes of the electron tubes

lead is. always desirable, the transmission frequency

Experience has shown that the amount of noise should be extended as far up as possible. this

of all these noise sources applies almost equally regardless of whether so-called frequency

is distributed over the entire frequency band. The band-splitting method can be used. Also

Playback is then insufficient if the eye in this process is namely the tape speed

my noise level is almost as high as the speed is much higher than the tape speed

like the amplitude of the signals to be reproduced. 30 when recording sound, and the tape consumption is

However, when playing back, the noise signal becomes very high. Furthermore, when downsizing

amplified simultaneously with the nut signals. From this the belt speed in this process

it follows that although the general noise level is the number of channels in which a recording is

When compared with the mean value of the amplitudes of the following, are increased, and herewith are higher costs

jutzsignals can be very small, but that in the 35 and more complicated recording and playback

connected to the lower frequency limit and the upper devices. Hence it is even with such

Cutoff frequency, with the signals of a very high method desirable to each individual channel in

Amplification need to use the ratio of the useful signal in the best possible way. In the end

Too noise signal drops sharply and the disturbing occurs with these methods also the problem that

Noise signal is therefore based on the lower and upper 40 phase position of the recorded in the individual tracks.

Concentrated land border, in the vicinity of which the greatest necessary signals must be carefully observed.

Reinforcement is needed. When recording and playing back a to

It depends on the special nature of the frequency band that descends to frequency zero reproducing signal depends on whether the noise signal is from the German Auslegeschrift 1 094 794 higher or lower frequency range or both 45 knows the frequency band into several sub-frequency noise signals cause the greatest trouble. to split ligaments and these after suitable Fre-Bei the reproduction of television signals, which sequence transformation in adjacent theoretically a frequency band of zero frequency tracks on a magnetogram carrier at the same time up to the frequency 4 MHz should be recorded because of the. To reduce the signal-to-noise ratio at very deep To improve periodic transmission of the black level corresponding to 50 frequencies, these deep speakers become Signals at the end of each line and at the quenzen before the recording of a special manual end each sub-image (series of lines) and subject to adjustment by using frequency or directions for the reintroduction of direct current amplitude modulation in a higher frequency position component, a record of extremely low-shifted. It is in this context gen frequencies unnecessary. Therefore, in the case of the 55, the entire Fre-Television is also known to be in a second track the high-frequency noise signal to record the frequency band and to play back the the greatest difficulty. Of course, the total frequency band can have a corresponding value Procedure to use sequence divider at the lower end of the tape as in the case of recording, that of the one recorded in the second track

The high-frequency components of a television 60 overall frequency band, the low frequencies in the gnals, can be divided into two categories. The same way as in the case of recording, ste includes the high-frequency components that are created before the residual frequency band with the depths recorded and reshaped by the first of the scanning of a part of the image field in which a sudden jump in brightness is reunited . This is well known. One speaks in this context of a 6 ₅ method has the disadvantage that there are several levels up front within the useful signal. These steep traces of drawing, or when applied to the Uber-Front, are transmitted by a frequency spectrum of message signals several transmissions, which theoretically require transmission channels to infinity.

5 6

It is also from the German patent, compress and after receiving or the

865 325 known, in the transmission of speech reproduction again at least partly based on its original

to improve the intelligibility by expanding the initial level. With this since

before the transmission leaves the higher speech frequencies known in 1924 dynamic control

increases and after the transfer there is more or less a relatively small improvement

niger weakens again. to improve the signal-to-noise ratio, as below

Also with the transmission and recording on the basis of a numerical comparison with the

and reproduction of other audio-frequency signals is "subject matter of the invention will be explained,

such predistortion and equalization are known. From Olson's book, "Acustical Enginee-

In image viewers which is an electronic ring, Princeton, New Jersey, 1957, pp. 420-422

see picture transmission system according to the television press finally to reduce interference in

zip, it is known to improve the recognizability of an audio signal, a non-linear EI-

ability to use details and contrast enhancement from the ment, through which those proportions

British patent 685 483 known in the course of a received or played signal whose

of the transmission path a non-linear amplification 15 amplitude below a given threshold

The transmission channel for the image values is to be provided, attenuated or completely suppressed.

signals behind this amplifier in two amplifier ends. By doing this, the audio signal

to split channels of controllable bandwidth and freed from noise components of low amplitude,

However, signals taken from these channels in antiphase are also those in the relevant channel

to be fed to the display unit after mixing. 20 parts of the useful signal lying in the amplitude range

It is suppressed for gamma correction of television signals. In a circuit arrangement for from US Pat. No. 2,697,758, the implementation of this known method is the signal to be corrected in a higher frequency band of the audio signal to be suppressed Frequencies containing frequency range and a divided the individual subbands and the subbands lower Frequencies containing frequency be- 25 the corresponding signal components are after richly divide and these frequency ranges, according to one or more of them a circuit anoro Expansion of the low-frequency range through voltage with non-linear transmission characteristics nonlinear gain to reunite. have gone through, reunited. The non-linear By dividing the signal into the two fre- circuit arrangement contains in particular pre-sequence areas, the expansion of the low frequency 30 charged diodes, the signals, their amplitude below the frequency range and the linear reunification of that determined by the preload A gamma threshold value should lie between the two frequency ranges, practically block and only the Correction without a noticeable increase in the interference component Signal components whose amplitude exceeds the threshold value can be achieved. To reduce the influence, let through. The resulting Obervon Interference is this well-known method neither 35 waves are undetermined by a downstream filter still suitable, suppressed. This known method is slow

Furthermore, from the "German Auslegeschrift is moderately complex, since two Banol ·

1 096 955 a method for recording vid filters are required, and it also has the disadvantage

cosignalen known on magnetic tape, in which that useful signals whose amplitude is below d ■

Video signal are above the highest threshold value to be transmitted, heavily attenuated or completely u;

low carrier video frequency can be suppressed with a.

compared to the video frequency band small hub The present invention is the object zi modulated in frequency and for which this is the case, based on the stars specified above tene frequency-modulated signal is inverted and that in technology is a method for reducing the inverted Signal is recorded. This method 45 of specifying the flow of interference signals that is broad to one due to the required carrier modulation, the message signal involved in a transmission «; dig and naturally requires a relatively wide frequency or recording or playback frequency band. gang are superimposed and in a certain;

It is also from the German patent specification of the frequency range of the message signal

658 976 known that atmospheric disturbances fall in the wired frequency band. The process *

to reduce loose recipients by the fact that it should be carried out with a simple device

the transmitted frequency band can be matched by filters and the useful signal has practically no effect

A few sub-areas are screened out and one rich in amplitude.

This object is performed according to the invention durci.

ratio of interference voltage amplitude to useful voltage 55 solved a method of the type mentioned

amplitude is greater than in the other areas is characterized in that the message

chen. The filtered out and limited frequency signal component, which contains the frequency range, ir

After this processing, the interfering signals will fall again before they are transmitted or

united with the rest of the signal. A limitation allows recording of a non-linear gain ml,

however, in systems where a high 60 is a gain factor that is an exponent

Fidelity is required, generally contains less than 1, and is subject to the Res

do not apply. of the message signal is reunited, unc:

From the "Textbook of Radio Reception Technology" that after receiving or reproducing the

von P i t s c h, Akademische Verlagsgesellschaft Nachrichtenensignals the message signal component, the

Geest & Portig K.G., Leipzig, 1948, pp. 659 and 660 65 were subjected to the non-linear amplification

is it known the dynamics, d. H. the ratio was, again separated, a non-linear amplification

loudest to the softest part of an acoustic signal with a gain factor that matches the

offer, before the broadcast or recording to exponents mentioned, reciprocal exponents

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holds, subjected and reused therein with the rest of the distortion. The signals in the

Message signal is combined. both channels are then added to each other,

This procedure eliminates the influence of disturbances, thereby restoring the original safety

ments that are superimposed on the message signal, gnale is completed. In color television,

after this the non-linear amplification with 5 if the so-called mixed heights in the

the exponent less than 1 has been subjected to drawing all color channels are added, these

is greatly reduced. It should be mentioned, however, that mixed heights may be ad-

the present proceedings have no influence on Stödiert. If the mixed highs are only in one

If the original signal has already been recorded, the signals become this

are superimposed. io channel after playback of all other signals

The following can be added in order to carry out the invention. Each of these two possibilities has to be approached: the si to be recorded - their advantages. When an addition to all the channels signals has taken place through a suitable filter network in the recording, at least two frequency bands or frequency ranges are divided up into a further statistical reduction of the noise signal. One of these frequency ranges 15 takes place, specifically by a factor of 1/1/3, since there can be three channels as the noise-loaded frequency range. However (since the very high ones are drawn and the other than the ratio frequencies play the greatest role) the phase-proportional noise-free frequency range. In the event of a surge in the recombination of the signals caused by the drawing of television signals, the so-called further reduction in the noise crossing point of the filter network can cancel out the advantages achieved. The choice point to be at which the reproduced signals of the system depends to a certain extent on half of their maximum energy level depending on how the signals are immediately after they have fallen, ie are three decibels lower, whether reproduction should be used ,
arguably the actual point of separation is not critical The amount of noise reduction that is itself. The signals in the noisy area 25 can thereby be achieved depends both on the pro-passage through a non-linear amplifier, in what proportionality factor with respect to the linearly amplified chem the instantaneous amplitude of the output signals, and on the reciprocal exponent signal proportional to a fractional power of the The gain of the non-linear amplifier is the instantaneous amplitude of the input signal. in recording and reproduction. For appa-The resulting output signal is then available for si- rative reasons, one will work with a gain signal of the same amplitude in the relative course according to a square root law and a somewhat noise-free range via a proportional- quadratic law. However, there can also be a relationship which is the product of a smaller exponent in the recording and larger constants and the original amplitude used to a fractional power of the larger exponent in the reproduction. The signals of the 35 den, so that one additional reduction of the noise-loaded area are achieved after this influence of the noise. The high-frequency amplification then back to the signals of the frequency components are added to the components. Lower band remainder in an adder circuit, and the frequency is superimposed. The greatest amplitudes occur; the signals combined in this way are usually, but not always, in the case of erratic signals. drawn. In a color television system, the 40 transitions in the signal when scanning sudden signals of the noisy area can be the so-called changes in brightness in the image field, and the th mixed heights and can either be too great amplitude then occurs where the deep fills three color component signals or only to sequence have their smallest amplitude,
added to a single color component signal. The dynamic range of each record will be added. 45 diums is limited, and usually you will

During playback, they will demand that this recording area be

to utilize the recorded signals from the usual scanning range as much as possible. When recording

direction removed, pre-amplified and preferential, one will therefore strive, if possible, to

wise also equalized, so that the signals up to the upper ximalamplitude of the nonlinear signal practically

Cutoff frequency in the same relative amplitudes 50 equal to the maximum amplitude of the same signal

which they make before recording before the non-linear amplification. the

possessed. After this equalization, the signals are subject to the maximum fluctuation range, which is

then divided into two channels, which receive the same visual signal (excluding the synchronous signals).

Own frequency ranges like the frequency ranges must be drawn, goes from the lightest white to

when recording. The signals of the rauschbelaste- 55 to complete black. The maximum amplitude

th area then pass through a non-linear one of the high-frequency signals that are recorded

Amplifiers or a non-linear network whose must correspond to this whole area, and

Properties inverse to the properties of the if the signal change is abrupt, the

amplifier or the network when recording the amplitude of the signals, which is the sum of the

are. This means that the output signals to the 60 represents high frequency components, equal to the am-

Signals in the input signal have a relationship to the amplitude of the lowest frequency or fundamental frequency

sen, which be a multiplication of the input signals of the jump. To change the dynamic range of the

to use the distortion network as well as possible with a factor ent- recording medium,

speaks through which the instantaneous amplitudes must be the output side of the non-linear amplifier

a power can be raised, which the reciprocal 65 in the noisy channel are set so,

Fractional power value in the record that when A ₀ equals the maximum of the signal,

represents, multiplied by the reciprocal value of which the transition from black to white on

Proportionality constants, which at the original output of the proportionate. noise-free channel

9 10

reproduces, the amplitude of a signal in the output becomes clear in the case in which

; of the non-linear channel, which shows a change in the - a large area of approximately maximum amplification

ben size reproduces the equation bA ^lln = A ₀ , which corresponds approximately to the black value.

speaks. Therein b is the constant of proportionality being sampled. The amplitude of the overall signal

and l / n is the fractional exponent. Likewise, 5 must then have the value one. When the entire signal is in

the output side of the non-linear amplifier would be compressed in the dynamics and that

Playback device the corresponding relationship follows the noise signal then introduced the specified

in the same way: (lib) A " = A _0. assumed value of 0.01 A ₀ would have, so would

Although these relationships allow a maximum utilization of the amplitude of the total signal between 0.99 A _{0 of} the recording medium and io and 1.01 A ₀ fluctuate. After squaring the maximum ratio of the useful signal to the interfering signal, these values were very approximately 0.98 and 1.02. To ensure the signal, it is not absolutely necessary - the noise component is almost doubled instead of realizing these relationships in practice. to be largely reduced. In use The only requirement that must be met in the band division method according to the invention is that the constant factor in the reproduction would be the amplitude fluctuation of the black area amplifier the reciprocal of the factor in the chensignal due to the noise ± 0.0001 A ₀ must have a non-linear recording amplifier, that is, there would be a difference in the noise and that the exponents of the signal amplitude functions of 48 db occur,
must also be reciprocal. Another advantage of the invention that maybe

If the conditions for the maximum Ausnut- ao are not immediately noticeable, is that through

tion of the dynamic range can be met and the invention the amplitude of triggered

the maximum signal amplitude assumed to be one oscillations is greatly reduced. Such suitable

is, then the constants b and Hb are also one-struck vibrations can be of a sharp

and in the following consideration, apart from a drop in the characteristic curve of the equalization circuit,

be careful. As said above, the 25 stirs are responsible for leveling the frequency response

Playback amplifier the main source of high frequencies near the cutoff frequency

Noise signal, and therefore intended to be used for the following. Such triggered vibrations

Discussion-these amplifiers as the only noise-interfering most with sudden changes of the

signal source can be viewed. At the terminals of the polarity or amplitude, and the amplitude of this

The playback head may let the noise signal 40 to 60 deci- 30 oscillations is proportional to the size of these

at are below the signal A ₀ , that is, there may be sudden changes.

amplitude ratio from 1: 100 to 1: 1000 present It represents a property of non-linear verse. If one assumes the smaller ratio, stronger with an exponential transfer function, and also assumes that a signal in the noisier exponent is <1, it shows that its gain decreases with the attached band before the non-linear gain, and there the amplitude equal to that of the noise signal ha- may be of smaller amplitudes, i.e. an amplitude of the size tude than the jump of the signal , if Er-0.01 A ₀ , then the same signal has, at the output of the non- The result is that a further reduction in the size of the linear recording amplifier an amplitude <amplitude is achieved. In the case of an amplifier with 0.1 A ₀ , ie it is reproduced with an amplitude of 40 quadratic transfer function that is 20 db above the noise signal. With the oscillation amplitude reduced from 10% to 1%, it is of course assumed that the noise signal in the present description means veau is measured after the equalization. . "Instantaneous value of the amplitude" is the absolute value

If the useful signal and the noise signal from the voltage or current of the signal without

were completely independent of one another, this would take into account its sign. It's not the Si

Signal level of 0.1 after squaring it with gnal as such, which was added during the recording

its original amplitude of 0.01 A ₀ appear, a fractional power and upon reproduction

while the noise signal with 0.0001 A ₀ appearing is raised to a power greater than one. When

would, d. H. with the hundredth part of this ampli- this would be the case and the reciprocal expo-

tude or with an amplitude that is 40 db smaller. 50 nents, for example, 0.5 and 2, the ideal would be

The noise signal, however, can be considered as a statistical signal of the recorded signal without meaning,

occur at the top of the useful signal, so that one and that of the reproduced signal would always be

Instantaneous value of the amplitude of 0.11 A ₀ occurring positive. In reality, however, every

which after its squaring an Am- drawn or reproduced signal in its fore

plitude of 0.0121, i.e. This means that a noise sign like the signal that is sent at the input of the

signal component of about Vs of the amplitude of the non-linear amplifier. The size of the Si

entire signal would be present. This means that its exponent would always contain which one

but that the useful signal, instead of being completely in that, is not the directly influenced parameter.

Noise signal go down, 14 db above the noise. An embodiment of the invention will now be

signal lies. _t 60 application explained in more detail with reference to the drawing.

The advantage, which by dividing the tape. Fig. 1 shows a block diagram of a system for

into a noisy signal and into a noiseless the recording of television signals;

Signal and by non-linear amplification only Fig. 2 shows the corresponding circuit diagram of a

of the noisy signal is reached, playback system performs for those with the facility

also from the fact that the, noise 65 Fig. 1 recorded signals;

the peak values of the low-frequency useful signals Fig. 3 is a circuit diagram of an amplifier whose

superimposed and that the non-linear amplifiers ent- output amplitude practically proportional to the qua-

amplify corresponding to the total amplitude. This is the third root of the input signals, and

11 12

F i g. 4 is a circuit diagram of an amplifier that exerts on be-. The relevant components are therefore

NEN output terminals supplies signals which are shown in FIG. 2 by the same reference numerals as in

rer amplitude proportional to the square of the ampli Fi g. 1, but marked with a line,

tuden are on its entrance side. indicated.

In the circuit according to FIG. 1, a signal 5 The signals recorded on the tape 19 can be

source 1 a television recording camera or among which removed by a scanning device 17 ',

May also be a television receiver. Which can be carried out in the same way as the recording

Output signals from the source 1 reach a line head 17 in FIG. 1 and which in many cases even

device 3, and this line can either be the complete scanning device. When playing

This scanning device initially supplies its signals with the inclusion of the direct current signal

components or a television signal, out to an amplifier 21.

which contains the lowest frequency components. In a practical implementation, this contains

have been removed by a blocking capacitor, amplifier several stages. Preferably the

so that they can be restored later in the usual way.

Need to become. When the signals to be recorded take place 15 sem points, so that the low-pass filter

be subjected to a frequency band division, 5 'and the delay line T supplied Si

the signal source 1 is the establishment of a channel in gnale the recorded frequencies with the same

which such a process takes place. Since the surfaces contain relative amplitudes like the signals,

Maintaining the precise phase relationships associated with the recording head 17 in FIG. 1 supplied

is of paramount importance in television signals, must be 20. However, they also contain the

that for the division of the signals into two channels, noise signals, which in the previous stages

one of which creates the low frequencies and the one. The filter 5 'and the delay line

other filters that carry high frequencies - T must be electrically identical to filter 5 and

network must be such that the phase delay of line 7 in FIG. Be 1, and the same is true of

tion is directly proportional to the frequency. This leaves 25 to the differential amplifier 9 '. As most of the

In the case of low-pass filters (Gaussian filters), the device used for the recording is relatively

easy to achieve, but cannot also be used for the playback process in the case of high-pass filters

just as easily possible. In the preferred embodiment, these circuit components need in many

In accordance with the embodiment of the invention, the initial cases simply simply exist and leave

voltage of the in F i g. 1 with 1 designated signal 30 by using a suitable switch from the

source are fed to two channels, one of which switches the recording side to the playback side.

Low-pass Gaussian filter 5 and the other a delay. The linear amplifier 13 can also be of the same type

Approximation line 7 contains which the entire signal can be constructed like the playback amplifier 13 '.

The amplifier 11 'does the reverse, however

hesitates, like the low frequencies in the lead, like the amplifier 11. It doesn't work

tion 5 experience. like the amplifier 11 after a square root

The signals of both channels are generated in a differential, but rather according to a square structure.

Reference amplifier 9 reunited with one another in wel- setz. So there are amplitude

chem the signals delivered by the filter from those which correspond to the square of the input amplitude

can be subtracted from the entire signal frequency band. The components 11 'and 13' are

den, so that only the high-frequency components at the adder circuit 15 ', its output

left over. These occur on the output side of the represents an image of the recorded signals. at

Differential amplifier on and become a non-li-the device described here gets this

near amplifier 11 supplied. At the same time, output signals are sent to a decoding device,

the signals supplied by the filter 5 to a linear 45 which the band splitting process that took place before the

Ren amplifier 13 is supplied. The output variables recording had taken place, again reversing,

These two amplifiers arrive at an adder, but since this has nothing to do with the invention,

circuit 15, which is known per se in any of this subsequent device in the drawing

Way can be constructed. One of these possibilities is not shown.

ten is a second differential amplifier, to which the 50 In the device described, the Si

Signals from one of the two channels with the reverse of the noisy channel only one

ter phase position are fed, so that the Addi- gen channel fed to which the low-frequency

tion by subtracting a negative quantity leads to relatively noise-free signals,

is effective. The combined signals, which are of course the high frequency components

probably the linearly amplified low-frequency components of the amplifier 11 'also more than one

nents as well as the non-linearly amplified high-frequency low-frequency channels via individual adding

sequence components contain ,,. be fed to a prayer. This possibility is always

known recording head 17 so that they are used to simplify the drawings and the

on fine recording tape 19 in the usual way, description not shown,

recorded * 60 In the above description of the block

In the case of the in FIG. 2 shown playback device circuit diagram according to F i g. 1 and 2 became the non-line the recording medium 19 is the same as near amplifiers 11 and 11 'only by their in Fig. 1. Each procedural step in the playback pre-functions is marked. The filters, the delay has its corresponding procedural step in connection lines, the linear amplifiers and the difder Recording. So it is for each of these 65 reference amplifiers as are the recording process steps a device is required which switches heads and pick-up heads so well-known as either identical to that in the recording channel elements that their description seemed superfluous, used device or the dual function are square and square root circuits

13 Ϊ4

also known. Various circuits fed to the DC power source, such as the anode of the tube Squaring and rooting; some of which 23, and the connection to the adder circuit 15 are more or less complicated, it contains a blocking capacitor 35. The tubes 23 Book "Waveforms", Vol. 19, Radiation Laboratory and 31 are in the usual way through Cathode Series (McGraw-Hill, 1949), on pp. 678 to 693 5 resistors 37 and 39 are prestressed. This rewriting, and it is also said there that some stands are not equipped with parallel capacitors Circuits can also take root from third parties, so that the tubes within certain limits nen. For the amplifier 11, each of the there can be stabilized by the negative feedback that occurs rooting circuits are used.

and for the amplifier 11 'each of the there involved changes. As is well known, the one crystal identical changes squaring circuits. Richter enforcing current approximates to that

It is not necessary that the amplifier 11 is a square of the voltage applied to the rectifier, Signal provides which is an integer exponent and, consequently, represents the one at such an equals corresponds to the square root of the voltage, provided that only the voltage lying around the exponent of the amplifier kers 11 'represents the reciprocal value of the amplifier 11 15 rectifier current. Each of these determinations represents. Nor is it necessary that the size "is tantamount to stating that the efalso of the exponent in amplifier Ii ', the amount 2 effective resistance of the device is inversely related to it has if it is only greater than 1, although the improvement of the applied voltage in the relevant half changes in terms of the ratio of the useful signal to the wave in which the rectifier durehläss-noise signal the larger the expo 20 is, the larger it is. The resistance changes in the blocking half-wave is made in amplifier 11 '. This fact in the same way but is so much higher Chen increase the scope of the invention that it is neglected in the present case and facilitate their implementation. To the can.

Corresponding circuits are illustrated in The impedance of each rectifier 29 is

Figs. 3 and 4 are shown. 25 for signals whose amplitudes are close to the

In the circuit of Fig. 3, the output noise signal level will be much less than that signal of the differential amplifier 9 to the grid of a resistor 25. In a first approximation one can therefore Five-pole tube 23 supplied. These tubes say that all of the Si properties provided by tube 23, that their dynamic internal resistance signals enforce the resistance of the rectifier, is very high and that its anode current is proportional to the output current of the tube within 30 and da is directly proportional to its input voltage over a considerable working range, the voltage is also on The rectifier connected to the tube 31 can be made tional of the control grid voltage. The internal resistance of these tubes can be proportional to the input voltage of tube 23. They can be regarded as infinite, and the ver is therefore proportional to the square root of the lattice strength output voltage is directly proportional to the 35 voltage of the tube 23.

Resistance of the load circuit. In reality, however, this is not strictly accurate.

At small signal amplitudes, at which the effective load circuit resistance is not made too high, the resistance of the rectifier is high, because otherwise the inevitable bypassing of high frequency components can inevitably reduce the high frequencies derived because the anode current of the tube 23 weaken. In the circuit shown in FIG. 3, it is the reverse of how the resistors are divided. If the anode voltage and the screen grid are assumed that the rectifier characteristics obey a voltage from an ordinary direct current source, the law of the square will change, and the anode will not receive its direct voltage from the grid of the tube 31 via a resistor 25 of 3000 ohms, since 45 exactly according to a square-root law, that is, it was found that at this value the exponent of A ₀ is not exactly 0.5, but the anode resistance the output characteristic is somewhat larger. However, it is still considerably smaller than one horizontally up to the cut-off frequency of 2 MHz. The same applies when it is used. the crystal rectifier has a cubic characteristic

The anode load circuit is connected via a block 50 or a characteristic curve with another expocapacitor 27, which is chosen as large as two.

is that it satisfactorily restores the signal within the frequency band from 1.2 to Um-

2 MHz provide a negligible impedance, it is necessary that the non-linear represents. The load circuit itself consists of two amplifiers 11 'has a characteristic which is the opposite of that of the polarized crystal rectifiers 29, 55 stronger 11 is as exactly reciprocal as possible. This leaves which are parallel to each other and lead to earth are achieved by creating a circuit. In the embodiment described here, which is practically dual that of the being two rectifiers "Hughes IN 191" amplifier 11, i.e. a circuit in which the applies, which have the same characteristics and resistances through conductance values, the currents through are suitable for high frequency. It is a matter of replacing 60 voltages and vice versa. Such a thing um, point contact rectifier. The rectifier ger amplifier is shown in FIG. 4 shown. In this 29 should be paired carefully, however, as the circuit will be one with a cathode resistor Characteristic curves of such rectifiers are not as uniform as inputs 42 connected as cathode amplifiers turn out like those of vacuum tubes. The tube 41 the signal of the differential amplifier 9 'to-high voltage side of these two rectifiers is 65 out. The property of this circuit is made with the grid of another amplifier tube 31 in that its output resistance is low and connected. The anode of the tube 31 is directly proportional to the voltage of the cathode via a ordinary load resistance 33 fluctuates from the same to the voltage of the grid, i.e. practically

15 16

table changes independently of the current. This applies to one another and not to individual ones

the requirement that the impedance of the rectifier.

The output circuit is relatively high in comparison. Other non-linear elements can be used instead of the internal resistance of the tube, instead of being the rectifier in the circuit, which is small compared to that in the recording circuit, provided that the dependence on their current is greater. The tube current flows through the cathode from its voltage in a manner which makes the resistance 42 of even higher resistance. suitable for the high frequencies to be treated The direct current component of the output signal is. If their characteristic curve symmetrically to the voltage is suppressed by a blocking capacitor 43, or runs to the current, one can also represent some of the switching elements in the frequency range used instead of the negligible resistance shown. Use on the rectifier networks. The blocking capacitors used are followed by two rectifiers 45, the amplifiers may not be connected in opposition to one another by themselves, but to the amplification factors which are in series with the proportionality blocking capacitors and do not correspond as in constant b or l / b , but this can be done Fig. 3 are guided to earth. Behind the rectifiers, a resistor 47 is routed to earth through the amplification of previous or rectifiers, compensate for subsequent amplifiers. The live end of which is located on the lattice of the output and the amplification or weakening in the output tube 49. This latter tube is dimensioned accordingly via a near low-frequency channel, a resistor 51 biased. It should be noted that the special reciprocal amplifiers described in the foregoing are not the only amplifiers and current that can be used for this, and the load circuit of the amplifier 11 'also does not necessarily have to have conductance values in parallel with a source constant The best amplifier for one contains resistors in series with a source. In the present constant tension. If the sum of the resistances is described, these of the 47 and the effective resistance of the tube 42 25 amplifier have been treated to show that the inventor has the same relationship to the effective resistance of the two amplifiers of the ratio rectifier network 45 as the conductance the moderately simple structure is feasible.
Resistance 25 to the conductance of rectifier 29, It should also be noted that the circuit in are thus the properties of the resistors in both F i g. 1 can also be used for purposes other than recording the cases and the output variables of the signals on the recording medium 19 when rectifiers have the desired properties. For example, you can use the sites. For this it is necessary that the resistor 47 use signals of the adder circuit 15 for modulating a small in relation to the minimum resistance of the carrier wave. The modulated carrier wave is both rectifier. The resistance of the rectifier can then be wirelessly or via a coaxial cable rectifier can be increased by remote transmission in each 35. There, the modulated branch of the rectifier network can receive a series carrier wave in the usual way and equalization can be performed by two or more than two rectifiers in order to apply the modulation voltage. This will also regain an equalization. The modulation voltage can be achieved in accordance with the characteristics of the rectifier, since one of the amplifier 21 in FIG. 2, the two series connections are then supplied to one another.

1 sheet of drawings

Claims (4)

1. ■ '■' ■ 2 ■■ ■ - Patent claims: 5. Device according to claim 3 or 4, characterized by an amplifier (13 or 1. Method for reducing the influence 13 ') with a linear gain factor for vervon Interference signals, which are a broadband re-strengthening of the remaining after the separation direction signal, in particular a television signal, 5 part of the message signal before the feed in the case of a transmission or a recording to the adding circuit (15 or 15 '). 6. Device according to Claim 3, 4 or 5, since den and in a certain frequency range characterized in that the separating device of the frequency taken by the message signal a low frequency fed with the message signal quenzbandes fall, in which the message io pass filter (5, 5 ') to separate a thereby one ten signal divided into message signal components suffering a delay of a predetermined amount which different frequency ranges of the lower-frequency signal component from the message Occupy the frequency band, and the message signal, also one with the message signal ten signal components after at least one fed delay device (7, T) for Circuit arrangement with non-linear transmission 15 introduction of a delay of the specified movement characteristic has passed through again size in the entire message signal, and one be agreed, thereby marked circuit arrangement (9, 9 ') for subtracting the net that the message signal component, which output signal of the low-pass filter from the occupies the frequency range (1.2 to 4 MHz), the output signal of the delay circuit under in which the interfering signals fall, before the transmission 20 generation of a higher-frequency signal component of the or recording a non-linear amplifier message signal. ·
kung with a gain factor that is one Contains exponents less than 1 _; ■ and with the rest of the message signal again is united, and that after the reception or 25
the playback of the message signal of the
Message signal component, that of the non-linear Reinforcement had been subjected to re-The present invention relates to a method separately, a non-linear gain with to reduce the influence of interfering signals, the a gain factor that corresponds to a broadband message signal, in particular mentioned exponents as reciprocal exponents holds, subjected and then superimposed again with the rest of the recording and reproducing process of the message signal is combined. and in a certain frequency range 2. The method as claimed in claim 1, characterized in that the Frekinds taken by the message signal that the first exponent falls about V2 35 frequency band, at which the message and the second exponent is about 2. signal is divided into message signal parts on which 3. Device for carrying out the transmission - different frequency ranges of the frequency band or recording method according to claim 1, taking, and the message signal components, after-characterized run through a frequency-selective at least one circuit arrangement with a separating device for separating the signal to 40 non-linear transmission characteristics partly, which has to be reunited mainly by the sturgeon. signals impaired frequency range contains, as is well known, all records available today are from the input of the separating device allocation process with regard to the frequency band of the transmitted message signal; further limited by a message signals to be stored. The non-linear amplifier (11) with the amplifier lower limit frequency is mostly determined by the display factor bA ^lln which the separated signal drawing method, while the upper part is supplied, and an adding circuit limit frequency up to a certain degree from the (15) to the Addition of the output signal of the non-apparatus system and in particular of the linear amplifier (11) and which depends on the speed of the recording medium. an optical gap of a photographic reproduction 4. Device for carrying out the receiving device or an air gap of a magnetic head or reproduction process according to Anfes. When the dimension of the scanner Claim 1, characterized by a separator or converter in the recording direction in the gross direction (5 ', 7', 9 ') for separating a signal arrangement of the wavelength of the portion to be reproduced the signal that comes to the transmission or recording side of the recorded signal can be separated Signal component which no longer perfectly reproduces the predominant signal signals impaired by the interference signals and finally disappears completely, contains the frequency range, corresponds to the received The output signal drops when approaching this NEN or reproduced message signal; 60 absolute cut-off frequency pretty fast and approx Rener by a non-linear amplifier (H ') shirt from linear. with the gain factor (Ub) A ", which the magnetic storage · of signals separated signal component is supplied, and the lower limit frequency is determined by an adder circuit (15 '), the inputs of which that the amplitude of the reproduced signal pro- Output signal of the non-linear amplifier and 65 proportional to the gradient of the magnetization of the is the part of the recording medium remaining after the separation, so that at low fre- received or reproduced messages the output signal a corresponding tensignals are supplied. has small amplitude. To a faithful reproduction