WO1998011674A1 - Procede et appareil permettant de supprimer les harmoniques superieurs d'emetteur ainsi que les signaux de blocage de recepteur - Google Patents

Procede et appareil permettant de supprimer les harmoniques superieurs d'emetteur ainsi que les signaux de blocage de recepteur Download PDF

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Publication number
WO1998011674A1
WO1998011674A1 PCT/SE1997/001495 SE9701495W WO9811674A1 WO 1998011674 A1 WO1998011674 A1 WO 1998011674A1 SE 9701495 W SE9701495 W SE 9701495W WO 9811674 A1 WO9811674 A1 WO 9811674A1
Authority
WO
WIPO (PCT)
Prior art keywords
low
pass filter
signals
received
antenna
Prior art date
Application number
PCT/SE1997/001495
Other languages
English (en)
Inventor
Lars Berggren
Hans Stattin
Christian Andersson
Anders Svensson
Hans Camper
Lars Nord
Original Assignee
Telefonaktiebolaget Lm Ericsson (Publ)
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 Telefonaktiebolaget Lm Ericsson (Publ) filed Critical Telefonaktiebolaget Lm Ericsson (Publ)
Priority to AU44053/97A priority Critical patent/AU4405397A/en
Publication of WO1998011674A1 publication Critical patent/WO1998011674A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits
    • H04B1/44—Transmit/receive switching
    • H04B1/48—Transmit/receive switching in circuits for connecting transmitter and receiver to a common transmission path, e.g. by energy of transmitter
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
    • H04B1/40—Circuits

Definitions

  • the present invention relates to radio communications systems, and more particularly to the suppression of undesirable signals arising in the transmit and receive signal processing paths of a radio transceiver.
  • RF radio-frequency
  • the performance of a radio-frequency (RF) transceiver is diminished any time interfering RF energy exists within that portion of the frequency spectrum allocated to the transceiver for transmission and reception.
  • RF energy existing outside the allocated spectrum For example, extraneous RF signals radiating at frequencies outside the designated reception bandwidth, but nonetheless picked up at the transceiver antenna, may prevent the transceiver from receiving signals of interest by driving sensitive, high-gain amplifiers within the transceiver into saturation.
  • extraneous RF signals lying outside the allocated receiver bandwidth may disrupt transceiver operation by mixing with harmonics produced by local oscillators used in the transceiver. These disruptive, outlying RF signals are often referred to in the art as receiver "blocking" signals.
  • the present invention fulfills the above-described and other needs by providing a radio transceiver which suppresses receiver blocking signals, as well as unwanted harmonics generated by components used in the transceiver during signal transmission, in an elegant and streamlined manner.
  • the present invention affords many advantages over prior art systems, for example, in terms of system stability, cost, complexity, and total part count.
  • the transceiver of the present invention includes a transmitter which generates information signals to be transmitted by the transceiver, and a receiver for processing information signals that are received by the transceiver.
  • a power amplifier connected to an output of the transmitter amplifies the information signals prior to their transmission, and a low-noise amplifier connected to an input of the receiver amplifies the received signals prior to their being processed.
  • a band-pass filter connected to an input of the low-noise amplifier filters the received signals prior to their amplification.
  • a switch is used to alternately connect a radio antenna of the transceiver to the output of the power amplifier in the transmit path and to the input of the band-pass filter in the receive path.
  • a bidirectional low-pass filter situated between the antenna and the switch, is used to filter both transmitted and received information signals.
  • the band-pass filter can be constructed to prevent receiver blocking signals from saturating the low-noise amplifier.
  • the bi-directional low-pass filter can be constructed, not only to prevent high-frequency receiver blocking signals from saturating the low-noise amplifier, but also to prevent the high-frequency receiver blocking signals from interfering with an intermediate frequency signal generated within the receiver. Additionally, the low-pass filter can be designed to attenuate harmonics, or overtones, generated during signal transmission.
  • Figure 1 is a block diagram of a prior art, two-way, time-division multiple-access (TDMA) radio transceiver.
  • Figure 2 is a block diagram of a prior art TDMA radio transceiver incorporating a discrete RF trap to reduce the effects of high-frequency blocking signals received at an antenna of the transceiver.
  • TDMA time-division multiple-access
  • FIG. 3 is a block diagram of an improved TDMA radio transceiver constructed in accordance with the teachings of the present invention.
  • FIG. 4 is a block diagram of an exemplary cellular mobile radiotelephone system constructed in accordance with the teachings of the present invention.
  • FIG. 1 depicts a conventional TDMA radio transceiver 100.
  • the conventional TDMA transceiver 100 includes an antenna 110 which is connected, by way of a standard TDMA switch 120, to an output of a transmit signal processing path and to an input of a receive signal processing path.
  • a power amplifier 160 is coupled to a low-pass filter 140 which is in turn coupled to one contact of the TDMA switch 120.
  • a second contact of the TDMA switch 120 is coupled to a band-pass filter 130 which is in turn coupled to a low-noise amplifier 150.
  • the low-noise amplifier 150 is in turn coupled to a heterodyne mixer 170.
  • the TDMA switch 120 alternately connects the transmit and receive signal processing paths to the antenna 110 in order to separate, and time-division multiplex, the transmission and reception processes.
  • the switch 120 is positioned such that the antenna 110 is isolated from the receive signal path and coupled to an output of the low-pass filter 140.
  • An information signal (TX) generated by a standard RF transmitter (not shown) is input to the power amplifier 160.
  • An amplified information signal, output from the power amplifier 160 is then input to the low-pass filter 140.
  • the low-pass filter 140 is used to attenuate unwanted harmonics, or overtones, generated by the transmitter and the power amplifier 160. As is well known in the art, such overtones arise at integer multiples of the transmit information signal (TX) carrier frequency.
  • the filtering characteristic of the low-pass filter 140 is set such that the amplified information signal may pass through the filter, while the higher-frequency overtones are attenuated.
  • An amplified, filtered information signal, output from the low-pass filter 140, is then coupled through the switch 120 to the antenna 110 for transmission.
  • the switch 120 is positioned such that the antenna 110 is isolated from the transmit signal path and coupled to an input of the band-pass filter 130.
  • An information signal received at the antenna is thus input to the band-pass filter 130 and then to the low- noise amplifier 150.
  • An amplified and filtered information signal, output from the low-noise amplifier 150, is input to the heterodyne mixer 170 and mixed with a local oscillator signal (LO) , as is well known in the art, in order to downconvert the received information signal carrier to an intermediate level .
  • LO local oscillator signal
  • An intermediate- frequency information signal (IF) is then passed to a standard RF receiver (not shown) for processing.
  • the low-noise amplifier 150 must have a relatively high gain characteristic in order to provide the mixer 170 with input signals of sufficient strength. As a result, excess RF energy applied to the input of low-noise amplifier 150 may drive the amplifier into saturation, and thereby compress, or block, received information signals.
  • the band-pass filter 130 is used to prevent extraneous, unwanted RF signals received at the antenna 110 from reaching the low-noise amplifier 150.
  • the filter characteristic of the band-pass filter 130 is set such that desired information signals may pass through the filter, while signals outside the allocated receiver bandwidth are attenuated. As is described in more detail below, however, the real-world filters used to realize the band-pass filter 130 do not, in many cases, adequately attenuate the harmful receiver blocking signals .
  • the heterodyne mixer 170 mixes received information signals with a local oscillator signal (LO) to produce an intermediate-frequency signal (IF) which is input to the receiver.
  • LO local oscillator
  • IF intermediate-frequency signal
  • the band-pass filter 130 is used to prevent such blocking signals from reaching the heterodyne mixer 170. Again, however, the parts commonly used to implement the band-pass filter 130 provide inadequate blocking signal suppression in many instances.
  • FIG. 2 depicts an RF trap comprising a single capacitor 180, those skilled in the art will appreciate that such an RF trap may include a combination of any number of passive components.
  • FIG. 3 depicts an exemplary TDMA transceiver 300 constructed in accordance with the teachings of the present invention.
  • the TDMA transceiver 300 includes an antenna 310 coupled to one port of a bi-directional low-pass filter 390.
  • a second port of the low-pass filter 390 is connected, by way of a TDMA switch 320, to an output of a transmit signal processing path and to an input of a receive signal processing path.
  • a power amplifier 360 is coupled to one contact of the TDMA switch 320.
  • a second contact of the TDMA switch 320 is coupled to a band-pass filter 330 which is in turn coupled to a low-noise amplifier 350.
  • the low-noise amplifier 350 is in turn coupled to a heterodyne mixer 370.
  • the TDMA switch 320 alternately connects the transmit and receive signal processing paths to the low-pass filter 390 in order to separate, and time- division multiplex, the transmission and reception processes.
  • the switch 320 is positioned such that the low-pass filter 390 is isolated from the receive signal path and coupled to an output of the power amplifier 360.
  • An information signal (TX) generated by a standard RF transmitter (not shown) is input to the power amplifier 360.
  • An amplified information signal, output from the power amplifier 360 is then coupled through the switch 320 to the low-pass filter 390.
  • the low-pass filter 390 is used during transmission to attenuate the unwanted overtones generated by the power amplifier 360.
  • An amplified, filtered information signal, output from the low-pass filter 390 is then coupled to the antenna 310 for transmission.
  • the switch 320 is positioned such that the low-pass filter 390 is isolated from the transmit signal path and coupled to an input of the band-pass filter 330.
  • An information signal received at the antenna 310 is thus input to the low-pass filter 390, then to the band-pass filter 330 and the low-noise amplifier 350.
  • the low-pass filter 390 and the band-pass filter 330 work together to eliminate the receiver blocking signals described above.
  • An amplified and filtered information signal, output from the low-noise amplifier 350 is input to the heterodyne mixer 370 and mixed with a local oscillator signal (LO) for downconversion.
  • An intermediate-frequency information signal (IF) output from the mixer 370, is then passed to a standard RF receiver (not shown) for processing.
  • the low-pass filter 390 is used to eliminate the harmonics generated by the power amplifier 360 during signal transmission and to attenuate high- frequency blocking signals during signal reception.
  • a ceramic RF filter can be used to implement the low-pass filter 390 of Figure 3. Because allocated RF transmit and receive bands are typically adjacent one another in the frequency spectrum, the cut-off frequency of the low-pass filter 390 can be set to pass the transmitted and received information signals while at the same time attenuating the higher-frequency receiver blocking signals and transmitter overtones. Thus, the cut-off frequency of the low-pass filter 390 will differ from that of low-pass filter 140.
  • low-pass filter 390 and band-pass filter 330 together achieve ' adequate receiver blocking signal attenuation without requiring that a complex RF filter, or a discrete RF trap, be used.
  • the band-pass filter 330 can be implemented using an already existing RF filter such as that used to implement the band-pass filter 130 of Figure 1. Also, by strategically using the low-pass filter 390 to serve dual roles in the transmit and receive signal processing paths, the total part count of the transceiver is not increased relative to the prior art system of Figure 1.
  • FIG. 4 is a block diagram of an exemplary cellular mobile radiotelephone system in which a transceiver constructed in accordance with the teachings of the present invention can be used.
  • the system shows an exemplary base station 410 and a mobile 420.
  • the base station 410 includes a control and processing unit 430 which is connected to a mobile switching center (MSC) 440 which in turn is connected to the public switched telephone network (not shown) .
  • the base station 410 also includes a voice channel transceiver 450 and a control channel transceiver 460.
  • the mobile 420 includes a voice and control channel transceiver 470 and a processing unit 480.
  • the base station transceivers 450, 460 and the mobile transceiver 470 can be constructed in accordance with the teachings of the present invention.
  • the base station 410 for a cell includes a plurality of voice channels handled by voice channel transceiver 450 which is controlled by the control and processing unit 430.
  • the control channel transceiver 460 is also controlled by the control and processing unit 430 and may be capable of handling more than one control channel.
  • the control channel transceiver 460 broadcasts control information over the control channel of the base station or cell to mobiles locked to that control channel .
  • the voice channel transceiver broadcasts the traffic or voice channels which can include digital control channel location information.
  • the mobile 420 periodically scans the control channels of base stations like base station 410 to determine which cell to lock on or camp to.
  • the mobile 420 receives absolute and relative information broadcast on a control channel at its voice and control channel transceiver 470.
  • the processing unit 480 evaluates the received control channel information which includes characteristics of the candidate cells and determines which cell the mobile should lock to.
  • the received control channel information not only includes absolute information concerning the cell with which it is associated, but also contains relative information concerning other cells proximate to the cell with which the control channel is associated.
  • These adjacent cells are periodically scanned by the mobile 420 while it is monitoring the primary control channel to determine if there is a more suitable candidate. Additional information relating to specifics of mobile and base station implementations can be found in copending U.S. Patent Application Serial No. 07/967,027 entitled "Multi- Mode Signal Processing" filed on October 27, 1992 to P. Dent and B. Ekelund, which disclosure is incorporated herein by reference.
  • the present invention teaches efficient, controllable techniques for eliminating receiver blocking signals using standard transceiver components. Overly complex RF filters and unreliable passive components are not required. Nor is an increase in the overall number of transceiver components required. It will be appreciated that the present invention is not limited to the specific illustrative embodiments described herein. The scope of the invention, therefore, is defined by the claims which are appended hereto, rather than the foregoing description. All equivalents which are consistent with the meaning of the claims are intended to be embraced therein.

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

Abstract

Cette invention a trait à un procédé ainsi qu'à l'appareil correspondant permettant de supprimer les harmoniques supérieurs d'émetteur ainsi que les signaux de blocage de récepteur dans un émetteur-récepteur. Dans un mode de réalisation exemplaire, l'émetteur-récepteur comporte un émetteur destiné à produire des signaux d'information, à émettre par le biais de l'émetteur-récepteur, et un récepteur ayant à traiter les signaux d'information en provenance de l'émetteur-récepteur. Un amplificateur de puissance, connecté à une sortie de l'émetteur, amplifie les signaux d'information avant leur émission et un amplificateur à faible niveau de bruit, connecté à une entrée du récepteur, amplifie les signaux reçus avant le traitement. De surcroît, un filtre passe-bande, connecté à une entrée de l'amplificateur à faible niveau de bruit, filtre les signaux reçus avant l'amplification et un commutateur, connectant, alternativement, une antenne radio de l'émetteur-récepteur à la sortie de l'amplificateur de puissance dans la voie d'émission ainsi qu'à l'entrée du filtre passe-bande dans la voie de réception, effectue un multiplexage par répartition dans le temps des signaux émis et reçus. On utilise un filtre passe-bas bidirectionnel, placé entre l'antenne et le commutateur, pour filtrer à la fois les signaux d'information émis et reçus. Les filtres passe-bande et passe-bas atténuent également des harmoniques supérieurs indésirables d'émetteur.
PCT/SE1997/001495 1996-09-10 1997-09-05 Procede et appareil permettant de supprimer les harmoniques superieurs d'emetteur ainsi que les signaux de blocage de recepteur WO1998011674A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU44053/97A AU4405397A (en) 1996-09-10 1997-09-05 Method and apparatus for suppressing transmitter overtones and receiver blocking signals in a radio transceiver

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US71002396A 1996-09-10 1996-09-10
US08/710,023 1996-09-10

Publications (1)

Publication Number Publication Date
WO1998011674A1 true WO1998011674A1 (fr) 1998-03-19

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PCT/SE1997/001495 WO1998011674A1 (fr) 1996-09-10 1997-09-05 Procede et appareil permettant de supprimer les harmoniques superieurs d'emetteur ainsi que les signaux de blocage de recepteur

Country Status (2)

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AU (1) AU4405397A (fr)
WO (1) WO1998011674A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003103156A2 (fr) * 2002-05-16 2003-12-11 Addvalue Technologies Ltd Circuit radioelectrique
US7796683B2 (en) * 2006-09-28 2010-09-14 Broadcom Corporation RF transceiver with power optimization
CN103220012A (zh) * 2013-05-08 2013-07-24 四川省艾普网络股份有限公司 一种wifi模块

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114944846B (zh) * 2021-02-10 2023-12-12 海能达通信股份有限公司 一种射频收发装置、方法和电子设备

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2257335A (en) * 1991-06-25 1993-01-06 Lk Products Oy Antenna switching circuit
US5355524A (en) * 1992-01-21 1994-10-11 Motorola, Inc. Integrated radio receiver/transmitter structure

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2257335A (en) * 1991-06-25 1993-01-06 Lk Products Oy Antenna switching circuit
US5355524A (en) * 1992-01-21 1994-10-11 Motorola, Inc. Integrated radio receiver/transmitter structure

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
KENWOOD: "TM-701A/E Service Manual", 1989, KENWOOD CORPORATION, TOKYO,JP, XP002026504 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003103156A2 (fr) * 2002-05-16 2003-12-11 Addvalue Technologies Ltd Circuit radioelectrique
WO2003103156A3 (fr) * 2002-05-16 2004-10-07 Addvalue Technologies Ltd Circuit radioelectrique
US7796683B2 (en) * 2006-09-28 2010-09-14 Broadcom Corporation RF transceiver with power optimization
CN103220012A (zh) * 2013-05-08 2013-07-24 四川省艾普网络股份有限公司 一种wifi模块

Also Published As

Publication number Publication date
AU4405397A (en) 1998-04-02

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