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WO1998009393A1 - Process for reducing internal interference in mobile radio apparatus - Google Patents

Process for reducing internal interference in mobile radio apparatus Download PDF

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Publication number
WO1998009393A1
WO1998009393A1 PCT/DE1997/001677 DE9701677W WO9809393A1 WO 1998009393 A1 WO1998009393 A1 WO 1998009393A1 DE 9701677 W DE9701677 W DE 9701677W WO 9809393 A1 WO9809393 A1 WO 9809393A1
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WO
WIPO (PCT)
Prior art keywords
reception
interference
system clock
clock
channels
Prior art date
Application number
PCT/DE1997/001677
Other languages
German (de)
French (fr)
Inventor
Bernhard Raaf
Original Assignee
Siemens Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens Aktiengesellschaft filed Critical Siemens Aktiengesellschaft
Publication of WO1998009393A1 publication Critical patent/WO1998009393A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B15/00—Suppression or limitation of noise or interference
    • H04B15/02—Reducing interference from electric apparatus by means located at or near the interfering apparatus
    • H04B15/04—Reducing interference from electric apparatus by means located at or near the interfering apparatus the interference being caused by substantially sinusoidal oscillations, e.g. in a receiver or in a tape-recorder
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B2215/00—Reducing interference at the transmission system level
    • H04B2215/064—Reduction of clock or synthesizer reference frequency harmonics

Definitions

  • the invention relates to a method for reducing the intrinsic interference of radio radios by harmonics of a system clock.
  • the mobile radio system can be in accordance with the GSM standard (radio transmission system in accordance with the recommendations of the CEPT sub-committee Group Special Mobile or Global System for Mobile Communication, GSM) or in accordance with the DECT standard
  • the exchanged digital data can be digitized voice signals, data for fax communication or more generally data for stationary or mobile data processing systems, such as personal computers or notebooks.
  • the DECT cordless telephone and the GSM mobile radio telephone are preferably audio message transmission systems which communicate in a radio network on predetermined transmission and reception channels via radio waves. It often happens that the reception on individual channels or frequencies is disturbed by the radio's own emission.
  • the term two-way radio here generally stands for a telephone that is wirelessly integrated into a radio network.
  • the disturbances come from harmonics from clocks required for signal processing, for example a system clock. In order to reduce these disturbances, complex shielding measures are necessary, especially within the device. With GSM, all signal processing clocks must be derived from a single system clock.
  • the invention has for its object to provide a method of the type mentioned.
  • the method according to the invention for reducing the interference in reception channels of a radio device caused by harmonics of a system clock or for reducing the interference in reception channels of radio devices in a radio network caused by harmonics of a system clock does not require any complex shielding measures in the radio device.
  • FIG. 1 shows the block diagram of a mobile radio device with the circuit blocks relevant to the invention
  • FIG 3 shows the position of a harmonic interference in a mobile radio device designed according to the invention.
  • the invention is based on the basic idea that the interference caused by the harmonics is at least reduced if the frequency of the interference is not centrally in the reception channel, but outside the bandwidth of the reception channel, for example between adjacent channels.
  • the receiving channels are defined so that the harmonics of the System clock caused interference is not in the center of a receiving channel.
  • the receive channels are placed so that the interference is outside the bandwidth of the receive channels, for example between two adjacent channels. Then the interference for each of the channels concerned is smaller than if a channel were centrally affected. This is an improvement, since generally no medium input sensitivity is required, but the requirements apply equally to all channels.
  • a somewhat changed system clock is used instead of the actual system clock specified by the definition of the signal modulation. This embodiment of the invention is described in more detail below.
  • FIG. 1 shows a mobile radio device MF, which is connected via an antenna A to a mobile radio system, not shown.
  • the antenna A is connected to a radio device FE which has an HF transceiver HSE.
  • the radio device FE is connected to a logic circuit LS.
  • the logic circuit LS is used for digital signal processing of the data transmitted between the mobile radio MF and the mobile radio system and for controlling the mobile radio MF itself.
  • a user interface and other circuit parts are of minor importance for the invention and are not shown in the drawing.
  • the HF transceiver device HSE is connected to a modulator-demodulator device MD.
  • the transmit and receive frequencies of the RF transmit / receive device HSE are regulated by a synthesizer SZ.
  • the reception period in the modulator-demodulator device MD is set, for example, by a period counter PZ. From the modulator demo dulator device MD, the demodulated received signal is passed on to the logic circuit LS.
  • a system clock is generated using a quartz QU in the radio device FE.
  • This system clock controls the HF transceiver HSE via the synthesizer SZ and the modulator-demodulator device MD via the period counter PZ. This is symbolically represented by the arrows P1 and P2.
  • the clocks and counter readings required for signal processing are derived from the system clock.
  • the receive frequency in the HF transceiver HSE is set by the system clock by means of the multiplication or division factor set in the synthesizer SZ.
  • the system cycle also determines the period duration by the end value of the counter reading in the period counter PZ.
  • the disturbance in FIG. 2 is located centrally in channel n.
  • the period is generated by the period counter PZ, which counts with a counting frequency of 0.462 us up to a final value of 10,000.
  • the interference is placed on the area outside the channel bandwidth, for example between the two adjacent channels n and n + 1.
  • System clock 13,0001 MHz
  • the original period of 4.62 ms is created from the changed system cycle by counting up to a final value of 9,999 instead of a final value of 10,000. This results in an inaccuracy of a maximum of half a cycle for all derived signals. This inaccuracy is tolerated by the GSM system.
  • the reception frequency is generated in a manner known per se from the system clock using the synthesizer SZ.
  • the frequency of the quartz QU changed due to the changed system clock must be taken into account.
  • the division or multiplication factor is increased or reduced in such a way that the original, predetermined value for the reception frequency is reached again.
  • the synthesizer can only be programmed in discrete steps, these steps must be fine enough to be able to set the reception frequency with the required accuracy.
  • the frequency of the quartz QU may have to be detuned slightly in order to achieve this accuracy. Such fine adjustment of the quartz QU is carried out anyway to correct the temperature drift and to compensate for the scatter of specimens.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Noise Elimination (AREA)

Abstract

This invention concerns a process for reducing interference in the reception channels of a radio telephony device caused by harmonics of a systems clock, according to which at least one reception clock with a preset frequency value for connection to a radio network for reception is derived from the system clock. In this process, the interference is displaced into the area outside of the band width of the receiving channel by a small change of the frequency of the system clock and the reception clock is regulated according to the preset frequency value.

Description

Beschreibungdescription
Verfahren zur Reduzierung der Eigenstörung in Mobilfunkgerä- tenProcedure for reducing self-interference in mobile radio devices
Die Erfindung betrifft ein Verfahren zur Reduzierung der Eigenstörung von Sprechfunkgeräten durch Oberwellen eines Systemtaktes .The invention relates to a method for reducing the intrinsic interference of radio radios by harmonics of a system clock.
Zwischen den Teilnehmern eines Mobilfunknetzes bzw. Mobil- funksystems können digitale Daten ausgetauscht werden. Das Mobilfunksystem kann gemäß dem GSM-Standard (Funkübertragungssystem gemäß den Empfehlungen des CEPT-Un- terauεschusses Group Special Mobile oder Global S_ystem for Mobile Communication, GSM) oder gemäß dem DECT-StandardDigital data can be exchanged between the participants in a mobile radio network or mobile radio system. The mobile radio system can be in accordance with the GSM standard (radio transmission system in accordance with the recommendations of the CEPT sub-committee Group Special Mobile or Global System for Mobile Communication, GSM) or in accordance with the DECT standard
(Digital European Cordless Telecommunication, DECT) ausgebildet sein.(Digital European Cordless Telecommunication, DECT).
Die ausgetauschten digitalen Daten können digitalisierte Sprachsignale, Daten zur Fax-Kommunikation oder ganz allgemein Daten für stationäre oder mobile Datenverarbeitungssysteme, wie Personal Computer oder Notebooks, sein.The exchanged digital data can be digitized voice signals, data for fax communication or more generally data for stationary or mobile data processing systems, such as personal computers or notebooks.
Das DECT-Schnurlostelefon und das GSM-Mobilfunktelefon sind vorzugsweise Audio-Nachrichtenübertragungssysteme, die in einem Funknetz auf vorgegebenen Sende- und Empfangskanälen über Radiowellen kommunizieren. Hierbei kommt es häufig vor, daß der Empfang auf einzelnen Kanälen bzw. Frequenzen durch Eigenemission des Sprechfunkgerätes gestört ist. Der Ausdruck Sprechfunkgerät steht hier allgemein für ein drahtlos in ein Funknetz eingebundenes Telefon. Die Störungen stammen von Oberwellen von zur Signalverarbeitung benötigten Takten, beispielsweise einem Systemtakt. Um diese Störungen zu mindern sind aufwendige Schirmungsmaßnahmen, vor allem innerhalb des Gerätes notwendig. Bei GSM müssen alle Signalverarbeitungstakte von einem einzigen Systemtakt abgeleitet sein. Der Erfindung liegt die Aufgabe zugrunde ein Verfahren der eingangs genannten Art anzugeben.The DECT cordless telephone and the GSM mobile radio telephone are preferably audio message transmission systems which communicate in a radio network on predetermined transmission and reception channels via radio waves. It often happens that the reception on individual channels or frequencies is disturbed by the radio's own emission. The term two-way radio here generally stands for a telephone that is wirelessly integrated into a radio network. The disturbances come from harmonics from clocks required for signal processing, for example a system clock. In order to reduce these disturbances, complex shielding measures are necessary, especially within the device. With GSM, all signal processing clocks must be derived from a single system clock. The invention has for its object to provide a method of the type mentioned.
Diese Aufgabe wird erfindungsgemäß durch die in den Patentan- spruch 1 bzw. 2 angegebenen Merkmale gelöst.According to the invention, this object is achieved by the features specified in patent claims 1 and 2.
Das erfindungsgemäße Verfahren zur Reduzierung der durch Oberwellen eines Systemtaktes verursachten Störung in Empfangskanälen eines Sprechfunkgerätes bzw. zur Reduzierung der durch Oberwellen eines Systemtaktes verursachten Störung in Empfangskanälen von Sprechfunkgeräten in einem Funknetz benötigt keine aufwendigen Schirmungsmaßnahmen im Sprechfunkgerät.The method according to the invention for reducing the interference in reception channels of a radio device caused by harmonics of a system clock or for reducing the interference in reception channels of radio devices in a radio network caused by harmonics of a system clock does not require any complex shielding measures in the radio device.
Im folgenden wird die Erfindung anhand eines in der Zeichnung dargestellten Ausführungsbeispiels beschrieben.In the following the invention will be described with reference to an embodiment shown in the drawing.
Dabei zeigenShow
FIG l das Blockschaltbild eines Mobilfunkgerätes mit den für die Erfindung relevanten Schaltungsblöcken,1 shows the block diagram of a mobile radio device with the circuit blocks relevant to the invention,
FIG 2 die Lage einer Oberwellen-Störung' bei einem kon- ventionellen Mobilfunkgerät, und2 shows the position of a harmonic interference in a conventional mobile radio device, and
FIG 3 die Lage einer Oberwellen-Störung bei einem erfindungsgemäß ausgebildeten Mobilfunkgerät.3 shows the position of a harmonic interference in a mobile radio device designed according to the invention.
Die Erfindung geht von der Grundidee aus, daß die durch die Oberwellen verursachte Störung zumindest reduziert wird, wenn die Frequenz der Störung nicht zentral im Empfangskanal liegt, sondern außerhalb der Bandbreite des Empfangskanales, beispielsweise zwischen benachbarten Kanälen.The invention is based on the basic idea that the interference caused by the harmonics is at least reduced if the frequency of the interference is not centrally in the reception channel, but outside the bandwidth of the reception channel, for example between adjacent channels.
Bei einer ersten Ausgestaltung der Erfindung werden die Empfangskanäle so definiert, daß die durch die Oberwellen des Systemtaktes verursachte Störung nicht im Zentrum eines Empfangskanals liegt. Die Empfangskanäle werden so gelegt, daß sich die Störung außerhalb der Bandbreite der Empfangskanäle befindet, beispielsweise zwischen zwei benachbarten Kanälen. Dann sind die Störungen für jeden der betroffenen Kanäle kleiner, als wenn ein Kanal zentral betroffen wäre. Dies stellt eine Verbesserung dar, da im allgemeinen nicht eine mittlere Eingangsempfindlichkeit gefordert wird, sondern die Anforderungen für alle Kanäle gleichermaßen gelten.In a first embodiment of the invention, the receiving channels are defined so that the harmonics of the System clock caused interference is not in the center of a receiving channel. The receive channels are placed so that the interference is outside the bandwidth of the receive channels, for example between two adjacent channels. Then the interference for each of the channels concerned is smaller than if a channel were centrally affected. This is an improvement, since generally no medium input sensitivity is required, but the requirements apply equally to all channels.
Bei einer zweiten Ausgestaltung der Erfindung wird statt des eigentlichen, durch die Definition der Signalmodulation vorgegebenen Systemtaktes ein etwas veränderter Systemtakt verwendet. Diese Ausführung der Erfindung wird im folgenden nä- her beschrieben.In a second embodiment of the invention, a somewhat changed system clock is used instead of the actual system clock specified by the definition of the signal modulation. This embodiment of the invention is described in more detail below.
In FIG l ist ein Mobilfunkgerät MF dargestellt, das über eine Antenne A mit einem nicht näher dargestellten Mobilfunksystem in Verbindung steht. Die Antenne A ist an einer Funkeinrich- tung FE angeschaltet, die eine HF-Sende-Empfangseinrichtung HSE aufweist. Die Funkeinrichtung FE ist mit einer Logikschaltung LS verbunden. Die Logikschaltung LS dient zur digitalen Signalverarbeitung der zwischen Mobilfunkgerät MF und Mobilfunksystem übertragenen Daten und zur Steuerung des Mo- bilfunkgerätes MF selbst.1 shows a mobile radio device MF, which is connected via an antenna A to a mobile radio system, not shown. The antenna A is connected to a radio device FE which has an HF transceiver HSE. The radio device FE is connected to a logic circuit LS. The logic circuit LS is used for digital signal processing of the data transmitted between the mobile radio MF and the mobile radio system and for controlling the mobile radio MF itself.
Eine Bedieneroberfläche und andere Schaltungsteile sind für die Erfindung von untergeordneter Bedeutung und in der Zeichnung nicht dargestellt.A user interface and other circuit parts are of minor importance for the invention and are not shown in the drawing.
In an sich bekannter Weise ist in der Funkeinrichtung FE die HF-Sende-Empfangseinrichtung HSE mit einer Modulator-Demodu- latoreinrichtung MD verbunden. Durch einen Synthesizer SZ werden die Sende- bzw. Empfangsfrequenzen der HF-Sende-Emp- fangseinrichtung HSE geregelt. Durch einen Periodenzähler PZ wird beispielsweise die Empfangsperiode in der Modulator-De- modulatoreinrichtung MD eingestellt. Von der Modulator-Demo- dulatoreinrichtung MD wird das demodulierte Empfangssignal an die Logikschaltung LS weitergegeben.In a manner known per se, in the radio device FE, the HF transceiver device HSE is connected to a modulator-demodulator device MD. The transmit and receive frequencies of the RF transmit / receive device HSE are regulated by a synthesizer SZ. The reception period in the modulator-demodulator device MD is set, for example, by a period counter PZ. From the modulator demo dulator device MD, the demodulated received signal is passed on to the logic circuit LS.
Unter Verwendung eines Quarzes QU in der Funkeinrichtung FE wird einen Systemtakt generiert. Von diesem Systemtakt werden über den Synthesizer SZ die HF-Sende-Empfangseinrichtung HSE und über den Periodenzähler PZ die Modulator-Demodulatorein- richtung MD angesteuert. Dies ist symbolisch durch die Pfeile Pl und P2 dargestellt. In den entsprechenden Baugruppen wer- den aus dem Systemtakt die zur Signalverarbeitung benötigten Takte und Zählerstände abgeleitet . Vom Systemtakt wird durch den im Synthesizer SZ eingestellten Multiplikations- bzw. Teilungsfaktor die Empfangsfrequenz in der HF-Sende-Empfangseinrichtung HSE eingestellt . Weiter wird vom Systemtakt die Periodendauer durch den Endwert des Zählerstandes im Periodenzählers PZ bestimmt.A system clock is generated using a quartz QU in the radio device FE. This system clock controls the HF transceiver HSE via the synthesizer SZ and the modulator-demodulator device MD via the period counter PZ. This is symbolically represented by the arrows P1 and P2. In the corresponding modules, the clocks and counter readings required for signal processing are derived from the system clock. The receive frequency in the HF transceiver HSE is set by the system clock by means of the multiplication or division factor set in the synthesizer SZ. The system cycle also determines the period duration by the end value of the counter reading in the period counter PZ.
Im folgenden wird auch auf die FIG 2 Bezug genommen.In the following, reference is also made to FIG.
Die Störung liegt in FIG 2 zentral im Kanal n. Dieser Darstellung liegen beispielsweise folgende Zahlenwerte zugrunde:The disturbance in FIG. 2 is located centrally in channel n.
Systemtakt 13 MHzSystem clock 13 MHz
Störung (zentral im Kanal n) 936 MHz=13-MHz * 72 Bandbreite +/-100 kHzInterference (central in channel n) 936 MHz = 13 MHz * 72 bandwidth +/- 100 kHz
Kanalabstand 200 kHzChannel spacing 200 kHz
Periodendauer 4,62 msPeriod duration 4.62 ms
Die Periodendauer wird durch den Periodenzähler PZ erzeugt, der mit einer Zählfrequenz von 0,462 us bis zu einem Endwert von 10.000 zählt.The period is generated by the period counter PZ, which counts with a counting frequency of 0.462 us up to a final value of 10,000.
Im folgenden wird auch auf die FIG 3 Bezug genommen.In the following, reference is also made to FIG.
Erfindungsgemäß wird die Störung auf den Bereich außerhalb der Kanalbandbreite gelegt, beispielsweise zwischen die beiden benachbarten Kanäle n und n+1. Systemtakt 13,0001 MHzAccording to the invention, the interference is placed on the area outside the channel bandwidth, for example between the two adjacent channels n and n + 1. System clock 13,0001 MHz
Störung (zwischen Kanal n und n+1) 936,1 MHz=13,0001 MHz*72 Bandbreite +/-100 kHzInterference (between channel n and n + 1) 936.1 MHz = 13.0001 MHz * 72 bandwidth +/- 100 kHz
Kanalabstand 200 kHz Periodendauer 4,62 msChannel spacing 200 kHz period 4.62 ms
Die ursprüngliche Periodendauer von 4,62 ms wird aus dem veränderten Systemtakt dadurch hergestellt, indem statt bis zu einem Endwert von 10.000 nur bis zu einem Endwert von 9.999 gezählt wird. Hierdurch ergibt sich bei allen abgeleiteten Signalen eine Ungenauigkeit von maximal einem halben Zyklus . Diese Ungenauigkeit wird vom GSM-System toleriert.The original period of 4.62 ms is created from the changed system cycle by counting up to a final value of 9,999 instead of a final value of 10,000. This results in an inaccuracy of a maximum of half a cycle for all derived signals. This inaccuracy is tolerated by the GSM system.
Die Empfangsfrequenz wird in an sich bekannter Weise aus dem Systemtakt mit Hilfe des Synthesizers SZ erzeugt. Bei der Programmierung des Synthesizers SZ muß die auf Grund des veränderten Systemtaktes veränderte Frequenz des Quarzes QU berücksichtigt werden. Der Teilungs- bzw. Multiplikationsfaktor wird derart vergrößert bzw. reduziert, so daß der ursprüngliche, vorgegebene Wert für die Empfangsfrequenz wieder er- reicht wird.The reception frequency is generated in a manner known per se from the system clock using the synthesizer SZ. When programming the synthesizer SZ, the frequency of the quartz QU changed due to the changed system clock must be taken into account. The division or multiplication factor is increased or reduced in such a way that the original, predetermined value for the reception frequency is reached again.
Falls der Synthesizer nur in diskreten Schritten programmierbar ist, so müssen diese Schritte fein genug sein, um die Empfangsfrequenz mit der geforderten Genauigkeit einstellen zu können. Unter Umständen muß die Frequenz des Quarzes QU geringfügig verstimmt werden, um diese Genauigkeit zu erreichen. Eine solche Feineinstellung des Quarzes QU wird sowieso zur Korrektur der Temperaturdrift und zum Ausgleich von Exemplarstreuungen durchgeführt.If the synthesizer can only be programmed in discrete steps, these steps must be fine enough to be able to set the reception frequency with the required accuracy. The frequency of the quartz QU may have to be detuned slightly in order to achieve this accuracy. Such fine adjustment of the quartz QU is carried out anyway to correct the temperature drift and to compensate for the scatter of specimens.
Für das erfindungsgemäße Verfahren ist außer dem Austausch des Quarzes QZ keine Änderung der Hardware der Mobilfunkgerä- tes MF notwendig. Es müssen nur die Bausteine in der Logikschaltung LS und in der Funkeinrichtung FE anders para e- triert werden. Dies ist durch eine vergleichsweise einfachen Änderung der Software in der Logikschaltung LS möglich. Apart from the exchange of the quartz QZ, no change in the hardware of the mobile radio device MF is necessary for the method according to the invention. Only the components in the logic circuit LS and in the radio device FE have to be parameterized differently. This is possible through a comparatively simple change in the software in the logic circuit LS.

Claims

Patentansprüche claims
1. Verfahren zur Reduzierung von einer, durch Oberwellen ei- nes Systemtaktes verursachten Störung in Empfangskanälen eines Sprechfunkgerätes, wobei aus dem Systemtakt mindestens ein Empfangstakt mit vorgegebenem Frequenzwert für die emp- fangsmäßige Anbindung an ein Funknetz abgeleitet wird, bei dem durch eine geringfügige Änderung der Frequenz des Systemtaktes die Störung in den Bereich außerhalb der Bandbreite des Empfangskanales verschoben wird, und bei dem der Empfangstakt auf den vorgegebenen Frequenzwert nachgeregelt wird.1. Method for reducing a disturbance in reception channels of a radiotelephone caused by harmonics of a system clock, at least one reception clock with a predetermined frequency value for the reception connection to a radio network being derived from the system clock, in which a slight change in the Frequency of the system clock the interference is shifted into the range outside the bandwidth of the reception channel, and at which the reception clock is readjusted to the predetermined frequency value.
2. Verfahren zur Reduzierung von einer, durch Oberwellen eines Systemtaktes verursachten Störung in Empfangskanälen von Sprechfunkgeräten in einem Funknetz, wobei aus dem Systemtakt mindestens ein Empfangstakt mit vorgegebenem Frequenzwert für die empfangsmäßige Anbindung an das Funknetz abgeleitet wird, bei dem durch die Vorgabe der Empfangskanäle die Störung in den Bereich außerhalb der Bandbreite der Empfangskanäle gelegt ist.2.Procedure for reducing interference in reception channels of radiotelephones in a radio network caused by harmonics of a system clock, at least one reception clock having a predetermined frequency value for the reception-based connection to the radio network being derived from the system clock, in which the input channels specify the Interference is placed in the area outside the bandwidth of the receiving channels.
3. Verfahren nach Anspruch 1 oder 2 , bei dem die Störung in den Bereich zwischen zwei benachbarte Empfangskanäle gelegt ist. 3. The method of claim 1 or 2, wherein the interference is placed in the area between two adjacent receiving channels.
PCT/DE1997/001677 1996-08-27 1997-08-07 Process for reducing internal interference in mobile radio apparatus WO1998009393A1 (en)

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DE19634613 1996-08-27
DE19634613.4 1996-08-27

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0988707A2 (en) * 1998-03-20 2000-03-29 Koninklijke Philips Electronics N.V. Receiver with a clock signal generator
WO2001031798A1 (en) * 1999-10-22 2001-05-03 Telefonaktiebolaget Lm Ericsson (Publ) Communications terminal having a receiver and method for removing known interferers from a digitized intermediate frequency signal

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0418149A2 (en) * 1989-09-13 1991-03-20 Sony Corporation Microcomputer controlled synthesizer-type radio receiver
GB2276784A (en) * 1993-03-22 1994-10-05 Motorola Gmbh Shifting spurious frequencies away from received frequency
WO1996037978A1 (en) * 1995-05-23 1996-11-28 Microunity Systems Engineering, Inc. Noise reduction in integrated circuits and circuit assemblies

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0418149A2 (en) * 1989-09-13 1991-03-20 Sony Corporation Microcomputer controlled synthesizer-type radio receiver
GB2276784A (en) * 1993-03-22 1994-10-05 Motorola Gmbh Shifting spurious frequencies away from received frequency
WO1996037978A1 (en) * 1995-05-23 1996-11-28 Microunity Systems Engineering, Inc. Noise reduction in integrated circuits and circuit assemblies

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0988707A2 (en) * 1998-03-20 2000-03-29 Koninklijke Philips Electronics N.V. Receiver with a clock signal generator
WO2001031798A1 (en) * 1999-10-22 2001-05-03 Telefonaktiebolaget Lm Ericsson (Publ) Communications terminal having a receiver and method for removing known interferers from a digitized intermediate frequency signal
US6373909B2 (en) 1999-10-22 2002-04-16 Telefonaktiebolaget Lm Ericsson (Publ) Communications terminal having a receiver and method for removing known interferers from a digitized intermediate frequency signal
CN100392988C (en) * 1999-10-22 2008-06-04 艾利森电话股份有限公司 Communication terminal with receiver for canceling known interfering signal from digitized intermediate frequency signal and method for canceling known interfering signal from digitized intermediate frequency signal

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