JPH04108228A - Transmitter-receiver - Google Patents

Abstract

PURPOSE:To quicken the rising of a burst signal and to reduce a change in a burst envelope by changing over an antenna changeover switch to the side of a transmitter till a bias circuit for a high frequency power amplifier rises from the coincidence detection of an identification code. CONSTITUTION:An antenna changeover switch 2 is changed over from the detection of coincidence of an identification code till a bias circuit of a high frequency power amplifier 49 rises. Then the bias circuit of the amplifier 49 is arisen for processing period during a prescribed standby period after the changeover switch 2 is thrown to the position of the transmitter 4 and a transmission signal is arisen after the lapse of the prescribed standby period. Thus, an antenna 1, the bias circuit of the amplifier 49 and a transmission signal are arisen in this order timewise in the case of transmission and then the bias circuit of the amplifier 49 is arisen before the transmission signal is arisen. Thus, the burst signal rising time is quickened and a change in the burst envelope is less.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is a paging system specified by the International Radiocommunication Consultative Committee (CC).
er) (reception) and a spread spectrum method (transmission), especially a transceiver suitable for a digital communication system using burst signals. The present invention relates to a transceiver comprising a receiver and a transmitter that transmits a burst signal subjected to spread spectrum modulation for a certain period of time after a certain waiting period from the time of coincidence detection.

(Prior art) A conventional transmitter/receiver of this type has an antenna l as shown in Fig. 4.
is the receiver 3 and transmitter 4 via the antenna selector switch 2.
The antenna changeover switch 2 is normally switched to the receiver 3 side. The receiver 3 is equipped with a detection circuit that receives a call signal from the base station and detects a match between the identification codes. When the detection circuit detects a match between the identification codes, the control circuit 5 controls the After the standby period, switch the antenna selector switch 2 to the transmitter 4 side for a certain period of time, and at the same time switch the antenna selector switch 2 to the transmitter 4 side.
The modulation circuit, the drive circuit, and the bias circuit of the high-frequency power amplifier are also switched to the operating state, and this switching simultaneously puts the transmission signal and the bias circuit of the high-frequency power amplifier into the operating state, and the transmitter 4 is put into the transmitting state. There is.

Systems such as positioning systems in which information signals are carried on burst signals, and spread spectrum communications require that the transmission signal rise quickly and that the burst envelope be constant.

Further, in spread spectrum modulation, etc., the RF output stage after modulation requires linear characteristics, so the final stage is composed of linear amplifiers. Therefore, when it comes to high-frequency power amplifiers, due to power consumption, the bias circuit is operated only when transmitting.

(Problem to be Solved by the Invention) However, when using the conventional transmitter/receiver described above, even though it takes time for the high frequency power amplifier to stabilize after the bias is turned on, the transmission signal and the bias circuit of the high frequency power amplifier Because the burst signal is started at the same time, there is a problem that the rise of the burst signal is delayed, and that the instant the burst signal rises, it causes unstable operation with a slight overshoot.

Also, the rise time delay is caused by spread spectrum modulation.
A problem arises in that correlation detection on the base station side is delayed by the amount of delay, and the correlation output waveform changes due to fluctuations in the burst envelope, and when the correlation output is used as positioning data, the threshold There was a problem that there was less margin.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transmitter/receiver in which the rise of a burst signal is made faster, unstable operation such as parasitic oscillation that tends to occur during an instantaneous period is reduced, and changes in the burst envelope are reduced.

(Means for Solving the Problems) The transmitter/receiver of the present invention includes a receiver equipped with a detection means for receiving a paging signal from a base station and detecting a match between identification codes, A transmitter/receiver comprising a transmitter that transmits a burst signal subjected to period spread spectrum modulation, and a first control means that starts the transmission signal after the predetermined standby period has elapsed, and a first control means that starts the transmission signal from a predetermined time within the predetermined standby period. A second control means for starting up the bias circuit of the amplifier, and a third control means for switching the antenna changeover switch to the transmitter side from the time when a match of the identification codes is detected to the time when the bias circuit of the high frequency power amplifier is started up. It is characterized by

(Function) In the transmitter/receiver of the present invention configured as described above, the antenna changeover switch is switched to the transmitter side between the time when a match of identification codes is detected and the time when the bias circuit of the high frequency power amplifier is started up. Since the bias circuit of the high frequency power amplifier is activated at a predetermined time during the fixed standby period after the signal is switched to the transmitter side, and the transmission signal is started after the elapse of the fixed standby period,
During transmission, the antenna, the bias circuit of the high-frequency power amplifier, and the transmission signal are activated in this order, and the bias circuit of the high-frequency power amplifier is activated before the transmission signal is activated. Even if it takes time for the high frequency power output device to stabilize, the high frequency power amplifier will already be in a stable state by the time the transmission signal is raised.

(Example) The present invention will be explained below with reference to Examples.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

In the case of the POC5AG code of the Bayesing system, the format of the signal transmitted from the base station is as shown in FIG. 2, for example. When a base station calls a transceiver, the data is in a batch format consisting of a preamble, a synchronization code, and an 8-frame code. The code of each frame includes an address code, which is an identification code of a predetermined bit length for specifying the transmitter and receiver;
It consists of a message code of a predetermined bit length.

On the receiver side, when the address code is the address code assigned to the receiver, an address match signal is output, and when an address match is detected, the period of one message code following the address code is set as a waiting period, and the waiting period elapses. The setting is such that one station can call in one frame by operating the transmission signal from the time of .

A signal transmitted from a base station is received by an antenna 1, and an output signal from the antenna 1 is input to a receiver 3 via an antenna changeover switch 2.

The receiver 3 includes an amplifier 31 that amplifies the received signal;
A bandpass filter 32 that inputs the output of and limits the band to a predetermined frequency bandwidth, a frequency converter 33 that reduces the frequency of the output signal from the bandpass filter 32, a buffer amplifier 35 that amplifies the frequency-converted signal, and a buffer amplifier. A bandpass filter 36 manually limits the output signal of 35 to a predetermined frequency bandwidth, a buffer amplifier 37 that amplifies the output signal from the bandpass filter 37, a demodulator 38 that demodulates the output signal from the buffer amplifier 37, It is equipped with a decoder 39 that detects from the demodulated output that the address code matches the address code assigned to the transmitter/receiver, and when it processes the received signal and detects a match between the address codes, the decoder outputs an address match signal. Output.

The transmitter 4 includes a temperature compensated crystal oscillator 41, a buffer amplifier 42 that amplifies the oscillation output of the temperature compensated crystal oscillator 41,
A modulator 43 that uses the output of the buffer amplifier 42 as a carrier and performs spread modulation using a PN code as a modulation signal, an amplifier 44 that amplifies the modulated output, and a bandpass that uses the amplified output of the amplifier 44 as input to limit the band to a predetermined frequency bandwidth. A filter 45, a frequency converter 46 which uses the output from the band-pass filter 45 as an input to increase the frequency, a band-pass filter 47 which uses the output of the frequency converter 46 as an input and limits the band to a predetermined frequency bandwidth, and a band-pass filter 47. It includes an amplifier 48 that amplifies the output, and a high frequency power amplifier 49 that amplifies the output of the amplifier 48, and supplies the output of the high frequency power amplifier 49 to the antenna 1 via the antenna changeover switch 2 for transmission.

On the other hand, a switching control circuit 51 switches the antenna switching switch 2 to the transmitter 4 side for a period from when the address matching signal is input until just before 1.5 frame length has elapsed. The bias circuit for controlling the bias circuit of the high frequency power amplifier 49 to be in the operating state during the period during which the antenna switching switch 49 is switched to the transmitter 4 side and slightly shorter than the period during which the antenna switching switch 2 is switched to the transmitter 4 side. The operation control circuit 52 and the drive circuit control the amplifiers 44 and 48 to be in the driving state for a period from when the address match signal is input until the bias circuit of the high frequency power amplifier 49 is stopped for a period of one message code. A control circuit 53 is provided.

In the transceiver of this embodiment configured as described above, F
Digitally modulated radio waves such as SK are received via the antenna l and the antenna changeover switch 2, amplified by the amplifier 31, band-limited to a predetermined bandwidth by the bandpass filter 32, frequency reduced by the frequency converter 33, and then buffered. It is amplified by an amplifier 35, band-limited to a predetermined bandwidth by a bandpass filter 36, and amplified by a buffer amplifier 37.
The demodulator 38 demodulates the signal. The demodulated digital signal is decoded by a decoder 39, and when the address code matches the address code assigned to the local station, a match signal is output.

On the other hand, on the transmitter 4 side, the oscillation output of the temperature compensated crystal oscillator 53 is amplified by the amplifier 42, the output from the amplifier 42 is used as a carrier signal, and the PN code is used as a modulation signal to be transmitted to the modulator 43.
The signal is spread spectrum modulated by the amplifier 44, and is amplified by the amplifier 44.
The band is limited to a predetermined frequency bandwidth by a band pass filter 45, the frequency is increased by a frequency converter 46, the band is limited to a predetermined frequency bandwidth by a band pass filter 47, and the amplifier 48 reaches a level capable of driving a high frequency power amplifier 49. The output of the amplifier 48 is power-amplified by a high-frequency power amplifier 49, and then applied to the antenna 1 via the antenna changeover switch 2 and transmitted. However, the power supply voltage of the amplifiers 44 and 48 is turned on and off under the control of the drive control circuit 53, and although the power supply voltage is applied to the high frequency power amplifier 49, the bias circuit of the high frequency power amplifier 49 is controlled by the bias operation control circuit 52. The operation of the antenna changeover switch 2 is controlled by a changeover control circuit 5.
Switched under the control of 1.

Normally, the antenna changeover switch 2 is switched to the receiver 3 side under the control of the changeover control circuit 51 and placed in the receiving state, and the power supply voltage is not applied to the amplifiers 44 and 48 under the control of the drive control circuit 52. First, amplifiers 44 and 48 are controlled to a non-driving state, and high frequency power amplifier 49
Although a power supply voltage is applied to the bias circuit, the bias circuit is controlled by a non-operating bias control circuit 53 to reduce power consumption.

In the receiving state, when the address codes match as described above, the decoder 39 outputs a match signal as shown in FIG. 3(a). In response to this match signal, the switching control circuit 51 switches the antenna selector switch 2 to the transmitter 4 side for a period of time from when the address match signal is input until just before 1.5 frames have elapsed, as shown in FIG. 3(b). A switching signal to switch to is output. Therefore, the antenna changeover switch 2 is switched to the transmitter 4 side during the period when the changeover signal is output, that is, from the time when the address match signal is input until just before 1.5 frames have elapsed, and enters a transmission standby state.

In addition, as shown in FIG. 3(c), the bias operation control circuit 52 indicates that the antenna changeover switch 2 is within the period in which the antenna changeover switch 2 is switched to the transmitter 4 side by the changeover control circuit 51, and the antenna changeover switch 2 is A control signal is output for controlling the bias circuit of the high frequency power amplifier 49 to the operating state for a period slightly shorter than the period during which it is switched to the transmitter 4 side. Therefore, the bias circuit of the high frequency power amplifier 49 is controlled to be in an operating state while the bias operation control signal is being output.

As shown in FIG. 3(d), the drive control circuit 53 drives the high frequency power amplifier 49 for a period of time from when the address match signal is input until the bias circuit of the high frequency power amplifier 49 stops operating for a period of one message code. A signal is output. Therefore, the amplifiers 44 and 48 receive the drive signal, a power supply voltage is applied during the output period of the drive signal, and the amplifiers 44 and 48 are driven during the output period of the drive signal, and the spread spectrum modulated transmission signal is amplified and input to the high frequency power amplifier 49. Ru. At this time, since the bias circuit of the high frequency power amplifier 49 has already passed approximately 1 message period from the time of startup, the high frequency power amplifier 49 is in a stable operating state, and at this point, the antenna 1 has already been switched to the transmitter 4 side. The amplified transmission signal is power amplified and the RF output signal is
As shown in Figure (d), the signal rises and is radiated from the antenna as a radio wave.

In addition, in the above embodiment, the case where the reception is a Basing system is illustrated, but the modulation method is not limited to FSK, but also PSK, PSK,
It can be applied to any system as long as it uses digital modulation such as GMSK modulation. Further, the transmitter can be applied to a case where information is transmitted in a burst signal and there is a time period between receiving the identification signal and transmitting it due to the system.

(Effects of the Invention) As explained above, according to the present invention, a transmission signal is started after a certain waiting period has elapsed from the time when a match of identification codes is detected, and the high frequency power amplifier is biased from a predetermined time within the certain waiting period. By starting up the circuit and switching the antenna selector switch to the transmitter side between when a match of identification codes is detected and when the bias circuit of the high-frequency power amplifier is started up, the burst signal rise time is faster and the fall time is shorter. It gets faster. Therefore, when a modulation signal such as spread spectrum modulation is carried on a burst signal, it is possible to prevent the beginning of the modulation information signal from being cut off at the rise of the signal.

Furthermore, the envelope of the burst signal becomes stable. Since the burst signal is stable, correlation output fluctuations at the receiver side are reduced.

Furthermore, unstable operation at the rising edge of transmission can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a schematic diagram showing an example of the format of a signal transmitted from a base station. FIG. 3 is a timing chart for explaining the operation of one embodiment of the present invention. FIG. 4 is a block diagram showing the configuration of a conventional example. 1... Antenna, 2... Antenna selection switch, 3
...Receiver, 4...Transmitter, 43...Modulator, 4
4 and 48...Amplifier, 49...High frequency power amplifier, 51...Switching control circuit, 52...Bias operation control circuit, 53...Drive control circuit.

Claims (1)

[Claims] A receiver equipped with a detection means for receiving a paging signal from a base station and detecting a match between identification codes, and a transmitter that transmits a burst signal subjected to spread spectrum modulation for a fixed period after a fixed waiting period from the time of detecting a match. A transmitter/receiver comprising: a first control means for starting a transmission signal after the elapse of the predetermined standby period; a second control means for starting a bias circuit of the high frequency power amplifier from a predetermined time within the predetermined standby period; and an identification code. A transmitter/receiver comprising: third control means for switching the antenna changeover switch to the transmitter side from the time of coincidence detection to the time of starting up the bias circuit of the high frequency power amplifier.