WO1998058455A1 - Transceiver stage for a mobile telecommunications unit - Google Patents

Transceiver stage for a mobile telecommunications unit Download PDF

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Publication number
WO1998058455A1
WO1998058455A1 PCT/GB1997/001649 GB9701649W WO9858455A1 WO 1998058455 A1 WO1998058455 A1 WO 1998058455A1 GB 9701649 W GB9701649 W GB 9701649W WO 9858455 A1 WO9858455 A1 WO 9858455A1
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WO
WIPO (PCT)
Prior art keywords
intermediate frequency
output
input
gain control
transmitter
Prior art date
Application number
PCT/GB1997/001649
Other languages
French (fr)
Inventor
Mike Ireland
Original Assignee
Maxon Systems Inc. (London) Ltd.
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 Maxon Systems Inc. (London) Ltd. filed Critical Maxon Systems Inc. (London) Ltd.
Priority to PCT/GB1997/001649 priority Critical patent/WO1998058455A1/en
Publication of WO1998058455A1 publication Critical patent/WO1998058455A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/52—TPC using AGC [Automatic Gain Control] circuits or amplifiers
    • 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

  • Transceiver stage for a mobile telecommunications unit
  • the present invention is related to a transceiver stage for a mobile telecommunications unit, preferably a handheld telephone utilising CDMA modulation technique.
  • a main problem in mobile handheld telephone units is the restricted battery capacity. Therefore, it is desirable to provide circuits for handheld telephone units requiring less power than conventional circuits. Moreover, conventional designs of transceiver stages require considerable space on the printed circuit board, are costly and time-demanding to calibrate.
  • the invention suggests a solution to overcome the above drawbacks.
  • the invention teaches a transceiver stage comprising: a receiver intermediate frequency input, a receiver intermediate frequency output, a transmitter intermediate frequency input, and a transmitter intermediate frequency output, an automatic gain control amplifier being provided with a gain control input, wherein an input of said automatic gain control amplifier is connected to said receiver intermediate frequency input and to said transmitter intermediate frequency input, and an output of said automatic gain control amplifier is connected to said receiver intermediate frequency output and to said transmitter intermediate frequency output.
  • the invention uses only one automatic gain control amplifier for both the receiver intermediate frequency signal and the transmitter intermediate frequency signal.
  • comparable prior art designs have two automatic gain control amplifiers: a first amplifier for the transmitter intermediate frequency signal and a second amplifier for the receiver intermediate frequency signal. This results in the gain characteristics of both amplifiers requiring to be calibrated. However, the temperature drift of these two amplifiers may still be different. Moreover, the gain characteristics of the two amplifiers may differ with variations in the supply voltage.
  • this invention reduces the number of active (power consuming) components in the transceiver stages. Moreover, this solution requires less space on the printed circuit board. Since according to the invention, only one automatic gain control amplifier is neccessary, the solution is also less costly and faster to produce and calibrate.
  • the invention makes use of the fact that interferences between the transmitter intermediate frequency signal and the receiver intermediate frequency signal are prevented by the duplex nature of the design. Moreover, only one amplifier (instead of two in prior art designs) needs to be calibrated. Any change in its gain characteristics affects both the transmitter intermediate frequency signal and the receiver intermediate frequency signal at the same time and in the same way. Therefore, there will be no net error in the system.
  • said input of said automatic gain control amplifier is connected to said receiver intermediate frequency input and to said transmitter intermediate frequency input via a summing junction combining the receiver intermediate frequency input signal and the transmitter intermediate frequency input signal and feeding the combined signal into the input of said automatic gain control amplifier.
  • said output of said automatic gain control amplifier is connected to said receiver intermediate frequency output and to said transmitter intermediate frequency output via a splitting junction feeding through a first output the output signal of said automatic gain control amplifier to said receiver intermediate frequency output and through a second output to said transmitter intermediate frequency output .
  • said first output of said splitting junction feeds the output signal of said automatic gain control amplifier via a first filter stage to said receiver intermediate frequency output.
  • said second output of said splitting junction feeds the output signal of said automatic gain control amplifier via a second filter stage to said transmitter intermediate frequency output.
  • Said first filter stage is dimensioned to substantially prevent the transmitter intermediate frequency output signal from occurring at the receiver intermediate frequency output.
  • said second filter stage is dimensioned to substantially prevent the receiver intermediate frequency output signal from occurring at the transmitter intermediate frequency output.
  • the filter stages are configured as upconverter roofing filters, UHF surface acoustical wave (SAW) filters, duplexers or the like.
  • SAW surface acoustical wave
  • the automatic gain control amplifier is calibrated via said gain control input to set the amplification factor of the receiver intermediate frequency output signal and of the transmitter intermediate frequency output signal.
  • said splitting junction is configured as a narrow band Wilkinson summing block.
  • other circuits are also possible to obtain the same effect.
  • said summing junction is configured as two filter stages, the first filter stage being dimensioned to allow the receiver intermediate frequency output signal to pass the first filter stage, and the second filter stage being dimensioned to allow the transmitter intermediate frequency output signal to pass the second filter stage.
  • the diagram shows a transceiver stage for a mobile handheld telephone unit utilising CDMA modulation technique.
  • the transceiver stage comprises a receiver intermediate frequency input RX_IF_Input, a receiver intermediate frequency output RX_IF_Output, a transmitter intermediate frequency input TX_IF_Input, and a transmitter intermediate frequency output TX_IF_Output.
  • an automatic gain control amplifier 10 having a gain control input GCI is provided.
  • An input 10a of said automatic gain control amplifier 10 is connected to said receiver intermediate frequency input RX_IF_Input and to said transmitter intermediate frequency input TX_IF_Input via a summing junction 12.
  • This summing junction 12 combines the receiver intermediate frequency input signal and the transmitter intermediate frequency input signal and feeding the combined signal into the input 10a of said automatic gain control amplifier 10.
  • the summing junction 12 is configured as a narrow band Wilkinson summing block formed of three identical delta-connected resistors.
  • An output 10b of said automatic gain control amplifier 10 is connected to said receiver intermediate frequency output RX_IF_Output and to said transmitter intermediate frequency output TX_IF_Output via a splitting junction 14 feeding through a first output 14a the output signal of said automatic gain control amplifier 10 via a first filter stage 16 to said receiver intermediate frequency output RX_IF_Output and through a second output 14b via a second filter stage 18 to said transmitter intermediate frequency output TX_IF_Output.
  • the first filter stage 16 is provided and dimensioned so as to substantially prevent the transmitter intermediate frequency output signal from occurring as a spurious signal at the receiver intermediate frequency output RX_IF_Output.
  • the second filter stage 18 is provided and dimensioned so as to substantially prevent the receiver intermediate frequency output signal from occurring at the transmitter intermediate frequency output TX_IF_Output .
  • the automatic gain control amplifier 10 is calibrated via said gain control input GCI to simultaneously set the amplification factor of the receiver intermediate frequency output signal and of the transmitter intermediate frequency output signal.
  • the splitting junction 14 is configured as two filter stages 14', 14" .
  • the input of the first filter stage 14' is connected to the output 10b of the amplifier 10.
  • the output of the first filter stage 14 ' is connected to the output 14a of the splitting junction 14.
  • the first filter stage 14" is dimensioned to allow the receiver intermediate frequency output signal to pass the first filter stage 14 ' , while substantially blocking the transmitter intermediate frequency output signal.
  • the input of the second filter stage 14" is also connected to the output 10b of the amplifier 10.
  • the output of the second filter stage 14" is connected to the output 14b of the splitting junction 14.
  • the second filter stage 14" is dimensioned to allow the transmitter intermediate frequency output signal to pass the second filter stage 14", while substantially blocking the receiver intermediate frequency output signal.

Abstract

A transceiver stage for a mobile telecommunications unit, preferably a handheld telephone unit utilising CDMA modulation technique, said transceiver stage comprising a receiver intermediate frequency input (RX-IF-Input), a receiver intermediate frequency output (RX-IF-Output), a transmitter intermediate frequency input (TX-IF-Input), and a transmitter intermediate frequency output (TX-IF-Output), an automatic gain control amplifier (10) being provided with a gain control input (GCI), wherein an input (10a) of said automatic gain control amplifier (10) is connected to said receiver intermediate frequency input (RX-IF-Input) and to said transmitter intermediate frequency input (TX-IF-Input), and an output (10b) of said automatic gain control amplifier (10) is connected to said receiver intermediate frequency output (RX-IF-Output) and to said transmitter intermediate frequency output (TX-IF-Output).

Description

Transceiver stage for a mobile telecommunications unit
Description
The present invention is related to a transceiver stage for a mobile telecommunications unit, preferably a handheld telephone utilising CDMA modulation technique.
A main problem in mobile handheld telephone units is the restricted battery capacity. Therefore, it is desirable to provide circuits for handheld telephone units requiring less power than conventional circuits. Moreover, conventional designs of transceiver stages require considerable space on the printed circuit board, are costly and time-demanding to calibrate.
In systems utilizing CDMA modulation it is a requirement that the phone should adjust its transmitter power in inverse proportion to the strength of the signal it receives from the local base station or network transceiver station to which it makes a link. Traditionally mobile telecommunications units utilizing CDMA modulation techniques have separate gain controlled amplifiers for their receiver and transmitter sections yet each of these are typically set to the same gain by the control systems in said mobile telecommunications unit.
The present invention suggests a solution to overcome the above drawbacks. In particular, the invention teaches a transceiver stage comprising: a receiver intermediate frequency input, a receiver intermediate frequency output, a transmitter intermediate frequency input, and a transmitter intermediate frequency output, an automatic gain control amplifier being provided with a gain control input, wherein an input of said automatic gain control amplifier is connected to said receiver intermediate frequency input and to said transmitter intermediate frequency input, and an output of said automatic gain control amplifier is connected to said receiver intermediate frequency output and to said transmitter intermediate frequency output.
In other words, the invention uses only one automatic gain control amplifier for both the receiver intermediate frequency signal and the transmitter intermediate frequency signal. In contrast thereto, comparable prior art designs have two automatic gain control amplifiers: a first amplifier for the transmitter intermediate frequency signal and a second amplifier for the receiver intermediate frequency signal. This results in the gain characteristics of both amplifiers requiring to be calibrated. However, the temperature drift of these two amplifiers may still be different. Moreover, the gain characteristics of the two amplifiers may differ with variations in the supply voltage.
As can be seen, this invention reduces the number of active (power consuming) components in the transceiver stages. Moreover, this solution requires less space on the printed circuit board. Since according to the invention, only one automatic gain control amplifier is neccessary, the solution is also less costly and faster to produce and calibrate.
The invention makes use of the fact that interferences between the transmitter intermediate frequency signal and the receiver intermediate frequency signal are prevented by the duplex nature of the design. Moreover, only one amplifier (instead of two in prior art designs) needs to be calibrated. Any change in its gain characteristics affects both the transmitter intermediate frequency signal and the receiver intermediate frequency signal at the same time and in the same way. Therefore, there will be no net error in the system. In a preferred embodiment of the transceiver stage according to the invention, said input of said automatic gain control amplifier is connected to said receiver intermediate frequency input and to said transmitter intermediate frequency input via a summing junction combining the receiver intermediate frequency input signal and the transmitter intermediate frequency input signal and feeding the combined signal into the input of said automatic gain control amplifier.
Preferably, said output of said automatic gain control amplifier is connected to said receiver intermediate frequency output and to said transmitter intermediate frequency output via a splitting junction feeding through a first output the output signal of said automatic gain control amplifier to said receiver intermediate frequency output and through a second output to said transmitter intermediate frequency output .
In a preferred embodiment of the invention, said first output of said splitting junction feeds the output signal of said automatic gain control amplifier via a first filter stage to said receiver intermediate frequency output.
Similarly, said second output of said splitting junction feeds the output signal of said automatic gain control amplifier via a second filter stage to said transmitter intermediate frequency output.
Said first filter stage is dimensioned to substantially prevent the transmitter intermediate frequency output signal from occurring at the receiver intermediate frequency output.
Likewise, said second filter stage is dimensioned to substantially prevent the receiver intermediate frequency output signal from occurring at the transmitter intermediate frequency output.
Since in prior art designs, such a filter stage is already present, this measure does not increase the overall number of components. In view of the 45 Mhz duplex spacing between the transmitter intermediate frequency signal and the receiver intermediate frequency signal, with the receiver intermediate frequency signal having a frequency of 85.38 Mhz, the achievable attenuation of undesired signal components should be sufficient.
The filter stages are configured as upconverter roofing filters, UHF surface acoustical wave (SAW) filters, duplexers or the like. Thus, the transmitter intermediate frequency signal is prevented from appearing as a spurious signal at the receiver intermediate frequency . output and a receiver intermediate frequency signal is prevented from appearing as a spurious signal at the transmitter intermediate frequency output .
The automatic gain control amplifier is calibrated via said gain control input to set the amplification factor of the receiver intermediate frequency output signal and of the transmitter intermediate frequency output signal.
In a preferred embodiment, said splitting junction is configured as a narrow band Wilkinson summing block. However, other circuits are also possible to obtain the same effect.
In a preferred embodiment, said summing junction is configured as two filter stages, the first filter stage being dimensioned to allow the receiver intermediate frequency output signal to pass the first filter stage, and the second filter stage being dimensioned to allow the transmitter intermediate frequency output signal to pass the second filter stage. Again, it is also possible to use other circuit designs to achieve the same results.
A presently preferred embodiment of the invention is described in greater detail with reference to the attached schematic circuit diagram. For the sake of conciseness, only the portion of the transceiver stage embodying the invention are described hereinafter and shown in the diagram.
The diagram shows a transceiver stage for a mobile handheld telephone unit utilising CDMA modulation technique. The transceiver stage comprises a receiver intermediate frequency input RX_IF_Input, a receiver intermediate frequency output RX_IF_Output, a transmitter intermediate frequency input TX_IF_Input, and a transmitter intermediate frequency output TX_IF_Output.
In the transceiver stage an automatic gain control amplifier 10 having a gain control input GCI is provided. An input 10a of said automatic gain control amplifier 10 is connected to said receiver intermediate frequency input RX_IF_Input and to said transmitter intermediate frequency input TX_IF_Input via a summing junction 12. This summing junction 12 combines the receiver intermediate frequency input signal and the transmitter intermediate frequency input signal and feeding the combined signal into the input 10a of said automatic gain control amplifier 10. The summing junction 12 is configured as a narrow band Wilkinson summing block formed of three identical delta-connected resistors.
An output 10b of said automatic gain control amplifier 10 is connected to said receiver intermediate frequency output RX_IF_Output and to said transmitter intermediate frequency output TX_IF_Output via a splitting junction 14 feeding through a first output 14a the output signal of said automatic gain control amplifier 10 via a first filter stage 16 to said receiver intermediate frequency output RX_IF_Output and through a second output 14b via a second filter stage 18 to said transmitter intermediate frequency output TX_IF_Output.
The first filter stage 16 is provided and dimensioned so as to substantially prevent the transmitter intermediate frequency output signal from occurring as a spurious signal at the receiver intermediate frequency output RX_IF_Output. Likewise, the second filter stage 18 is provided and dimensioned so as to substantially prevent the receiver intermediate frequency output signal from occurring at the transmitter intermediate frequency output TX_IF_Output .
The automatic gain control amplifier 10 is calibrated via said gain control input GCI to simultaneously set the amplification factor of the receiver intermediate frequency output signal and of the transmitter intermediate frequency output signal.
The splitting junction 14 is configured as two filter stages 14', 14" . The input of the first filter stage 14' is connected to the output 10b of the amplifier 10. The output of the first filter stage 14 ' is connected to the output 14a of the splitting junction 14. The first filter stage 14" is dimensioned to allow the receiver intermediate frequency output signal to pass the first filter stage 14 ' , while substantially blocking the transmitter intermediate frequency output signal.
The input of the second filter stage 14" is also connected to the output 10b of the amplifier 10. The output of the second filter stage 14" is connected to the output 14b of the splitting junction 14. The second filter stage 14" is dimensioned to allow the transmitter intermediate frequency output signal to pass the second filter stage 14", while substantially blocking the receiver intermediate frequency output signal.

Claims

1. Transceiver stage for a mobile telecommunications unit, preferably a handheld telephone unit utilising CDMA modulation technique; said transceiver stage comprising: - a receiver intermediate frequency input (RX_IF_Input) ;
- a receiver intermediate frequency output (RX_IF_Output) ;
- a transmitter intermediate frequency input (TX_IF_Input) ; and
- a transmitter intermediate frequency output (TX_IF_Output) ; - an automatic gain control amplifier (10) being provided with a gain control input (GCI) ; wherein
- an input (10a) of said automatic gain control amplifier (10) is connected to said receiver intermediate frequency input (RX_IF_Input) and to said transmitter intermediate frequency input (TX_IF_Input) ; and
- an output (10b) of said automatic gain control amplifier (10) is connected to said receiver intermediate frequency output (RX_IF_Output) and to said transmitter intermediate frequency output (TX_IF_Output) .
2. Transceiver stage according to claim 1, wherein
- said input (10a) of said automatic gain control amplifier (10) is connected to said receiver intermediate frequency input (RX_IF_Input) and to said transmitter intermediate frequency input (TX_IF_Input) via a summing junction (12) combining the receiver intermediate frequency input signal and the transmitter intermediate frequency input signal and feeding the combined signal into the input (10a) of said automatic gain control amplifier (10) .
3. Transceiver stage according to claim 1, wherein
- said output (10b) of said automatic gain control amplifier (10) is connected to said receiver intermediate frequency output (RX_IF_Output) and to said transmitter intermediate frequency output (TX_IF_Output) via a splitting junction (14) feeding through a first output (14a) the output signal of said automatic gain control amplifier (10) to said receiver intermediate frequency output (RX_IF_Output) and through a second output (14b) to said transmitter intermediate frequency output (TX_IF_Output) .
4. Transceiver stage according to claim 3, wherein
- said first output (14a) of said splitting junction (14) feeds the output signal of said automatic gain control amplifier (10) via a first filter stage (16) to said receiver intermediate frequency output (RX_IF__Output) .
5. Transceiver stage according to claim 3, wherein
- said second output (14b) of said splitting junction (14) feeds the output signal of said automatic gain control amplifier (10) via a second filter stage (18) to said transmitter intermediate frequency output (TX_IF_Output) .
6. Transceiver stage according to claim 4, wherein said first filter stage (16) is dimensioned to substantially prevent the transmitter intermediate frequency output signal from occurring at the receiver intermediate frequency output (RX_IF_Output) .
7. Transceiver stage according to claim 5, wherein - said second filter stage (18) is dimensioned to substantially prevent the receiver intermediate frequency output signal from occurring at the transmitter intermediate frequency output (TX_IF_Output) .
8. Transceiver stage according to claim 5, wherein
- said automatic gain control amplifier (10) is calibrated via said gain control input (GCI) to set the amplification factor of the receiver intermediate frequency output signal and of the transmitter intermediate frequency output signal.
9. Transceiver stage according to claim 3, wherein
- said summing junction (14) is configured as a narrow band Wilkinson summing block.
10. Transceiver stage according to claim 4, wherein
- said splitting junction (16) is configured as two filter stages (14', 14"), the first filter stage (14') being dimensioned to allow the receiver intermediate frequency output signal to pass the first filter stage (141), and the second filter stage (14") being dimensioned to allow the transmitter intermediate frequency output signal to pass the second filter stage (14") .
PCT/GB1997/001649 1997-06-19 1997-06-19 Transceiver stage for a mobile telecommunications unit WO1998058455A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/GB1997/001649 WO1998058455A1 (en) 1997-06-19 1997-06-19 Transceiver stage for a mobile telecommunications unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/GB1997/001649 WO1998058455A1 (en) 1997-06-19 1997-06-19 Transceiver stage for a mobile telecommunications unit

Publications (1)

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WO1998058455A1 true WO1998058455A1 (en) 1998-12-23

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PCT/GB1997/001649 WO1998058455A1 (en) 1997-06-19 1997-06-19 Transceiver stage for a mobile telecommunications unit

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0210606A2 (en) * 1985-08-01 1987-02-04 Rohde & Schwarz GmbH & Co. KG Circuit for the decoupled combining of the output powers of several high-frequency power emitters
WO1987002538A1 (en) * 1985-10-15 1987-04-23 Minori Kawano Cellular radio telephone enhancement circuit
WO1993010609A1 (en) * 1991-11-19 1993-05-27 Interdigital Communications Corporation Adaptive power control for a spread spectrum communications system and method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0210606A2 (en) * 1985-08-01 1987-02-04 Rohde & Schwarz GmbH & Co. KG Circuit for the decoupled combining of the output powers of several high-frequency power emitters
WO1987002538A1 (en) * 1985-10-15 1987-04-23 Minori Kawano Cellular radio telephone enhancement circuit
WO1993010609A1 (en) * 1991-11-19 1993-05-27 Interdigital Communications Corporation Adaptive power control for a spread spectrum communications system and method

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