SU492918A1 - Device for demodulating a two-stage pulse-width modulated pulse signal - Google Patents

Description

(54) DEVICE FOR DEMODUIIAADIUM HYGOSITIONAL

latitude-modulated imggu; 1st sIGNAL

I

The invention relates to instrumentation and can be used in digital magnetic recording apparatus.

The known devices for the demodulation of a two-positioned width-controlled signal, comprising a reproducing magnetic head, an amplifier, a driver-limiter, an adder and a demodulator, are characterized by relatively low noise immunity and sensitivity to abrupt changes in the speed of the recording medium.

The purpose of the invention is to improve noise immunity and enable operation with abrupt changes in the speed of the recording medium.

For this, in the proposed device, the output of the limiter imager is connected to the inputs of two demodulator integrators, whose outputs through the differential amplifier are connected to a bchoi pulse signal, and the input of the sync signal forks, and the output of the pulse signal generator is switched on. The first input of the adder, on

the other input of which and to the integrator reset inputs is connected to the output of the clock signal generator.

The drawing shows the structural scheme of the proposed device for the demodulation of a two-stage width-modulated pulse signal.

The device contains a series-connected reproducing magnetic

head 1, amplifier 2, driver limiter 3, the output of which is connected to two integrators 4 and 5 of demodulator 6 and to driver synchronization signal 7. The device also contains a differential amplifier 8, driver of pulse signals 9 and adder 1O. The outputs of the integrators 4 and 5 are connected to the input of the differential amplifier 8, the output of which is connected to the driver 9. Output

the latter is connected to the first input of the bit mator 10, with the second input of which and the reset inputs of the integrators 4 and 5 connected the output of the imager 7.

Information signal recorded on

magnetic tape, magnet is reproduced

Head 1, the voltage from the output of which is amplified by amplifier 2 and limited by driver-limiter 3. At the output of the latter, a two-way, one-way-width-modulated pulse signal (ORIM) is formed, at which, the unit of the information sequence corresponds to a pulse of 2/3 T. Where T is the period of the sync signal fixed to the timing signal (the front of the OMR signal), and zero pulses of 1/3 T duration. The signal generated by OSHIL1 is fed to the input of the ramp 7, which also generates the pulses of the sync signal and is also fed to the input of the integrators 4 and 5 demodul of torus 6, which separately integrates the half-waves of negative and positive polarities. Resetting the gamers' impulses. The telem 8, from the output voltage of which, using the shaper 9, generates pulses corresponding to the information sequence zero.The use of two integrators 4 and 5 and the differential amplifier 8 in the circuit implements the principle of relative detection, which causes increased noise immunity and low sensitivity of the device to the speed of the recording medium was fluctuated; Discount sequence.

Subject invention

A device for demodulating a two-position pulse-width modulated pulse containing a reproducing magnetic head, an amplifier, a driver-limiter, connected in series with each other, and a demodulator, condition. of the two integrators, the differential amplifier and the pulse generator, as well as the sync driver and the adder, which, in order to improve noise immunity and enable operation with abrupt changes in the speed of the recording medium, the output of the limiter to the two integrator integrators of the demoduglator, whose outputs through the differential amplifier are connected to the input of the pulse former, and the input of the clock signal generator, and the output of the pulse generator mpulsnyh signals connected to the first input of the adder, the other input of which integrator and reset inputs are connected to the output of the n-sinhrosig 1la.