JPH1051252A - Radio equipment and gain control circuit for radio equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the gain control circuit in which high performance transmission power control and circuit miniaturization are realized simultaneously. SOLUTION: A base-band signal is given to a modulation section 26 at a transmitter side, in which the signal is modulated into an intermediate frequency signal, and converted into a high-frequency signal at a frequency conversion section 28 via a gain variable amplifier circuit 27 and amplified and outputted by a highfrequency amplifier 29. A transmission output is converted into an intermediate frequency signal by a frequency conversion section 34, and the converted signal is given to a signal changeover device 33. The signal changeover device 33 receives and selects the signals in time division, and its output is given to a logarithmic amplification detection circuit 32, in which a transmission level is detected, the signal denoting the level is converted into a digital signal by an A/D converter 31 and the digital signal is given to a control section 30. The control section 30 controls the gain variable amplifier circuit 27, so that the transmission output level is made constant based on the received data. A reception signal converted into an intermediate frequency signal by a frequency conversion section 38 at a receiver side is received via a signal changeover device 33, the resulting signal is given to a control section 30 after voltage detection and digital conversion, and the control section 30 controls a gain variable amplifier circuit 39, so that the signal level is made constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a transmission system and a reception system gain control circuit used in a radio.

[0002]

2. Description of the Related Art In a conventional radio, an APC (Auto Power Control) for monitoring a decrease in transmission power of a high-frequency amplifier due to a temperature change or the like and controlling the transmission power to a constant output power.
Control circuit and an AGC (Auto Gai) to reduce fluctuations in demodulation output due to fluctuations in reception input.
n Control) circuit is provided. FIG. 3 shows a configuration of a gain control circuit of a conventional wireless device. The baseband signal is modulated to an intermediate frequency by the modulator 11 and input to the frequency converter 13 via the variable gain amplifier 12. In the frequency conversion unit 13, the input signal is frequency-converted into a high-frequency signal for wireless transmission at the local frequency generated by the local oscillator 18, and the converted signal is amplified by the high-frequency amplifier 14 and transmitted from the antenna 20 through the antenna duplexer 19. Radiated into the air.

A power detection circuit 17 usually uses a device such as a PIN diode to detect the output level of the high-frequency amplifier 14.
Is converted into a digital signal and input to the control unit 15. The control unit 15 controls the voltage control gain variable amplifier circuit 12 based on the input data so that the transmission output level becomes constant.

In the receiving section, the signal received by the antenna 20 is input to the frequency converting section 21 via the antenna duplexer 19, and the signal of the
The converted signal is converted into an intermediate frequency around z, and the converted signal is input to the variable gain amplifier 24 and the logarithmic amplification detector 22. The logarithmic amplification detection circuit uses RSSI (Receiveds
signal strength indicator)
It is also called, and measures the electric field strength of the receiver, and performs the AGC operation based on this signal. The signal of the logarithmic amplification detection circuit 22 is converted into a digital signal by the AD converter 23, and is input to the control unit 15, and the gain is changed so that the signal level input from the variable gain amplification circuit 24 to the demodulation unit 25 becomes constant. The amplifier circuit 24 is controlled.

[0005]

In the above, since the transmission frequency of a normal radio is as high as several hundred MHz to several GHz, a general-purpose logarithmic amplifier for inputting an intermediate frequency band is required to detect the electric field strength. Cannot be used. Therefore, P
Power detection circuit 1 using a device such as an IN diode
7.

FIG. 4 shows an input / output relationship of a detection circuit using a PIN diode. The horizontal axis represents the coupling input level from the antenna output, and the vertical axis represents the detection voltage. As shown in this figure, P
In the detection circuit using the IN diode, only a dynamic range of about 30 dB can be obtained, and the characteristics become non-linear when the input level is high and when it is low. Processing is required. In addition, there is a problem that transmission power of 30 dB or more cannot be detected due to a single characteristic of the PIN diode.

Further, a circuit for detecting the transmission power and the reception power and an AD converter thereof are required, and a correction circuit is required because the slopes of the detection voltages are different.
There is also a problem that the hardware scale becomes large.

It is an object of the present invention to provide a gain control circuit that solves the above-mentioned problems in the conventional configuration and can simultaneously realize high-performance transmission power control and downsizing of the circuit.

[0009]

The object of the present invention is to provide a gain control circuit of a radio device for converting a frequency of an output signal on a transmission side into an intermediate frequency, a transmission power level of the frequency conversion section and a reception side. This is achieved by providing the signal input side of the gain control unit with a signal switching unit that switches the signal of the reception power level of the frequency conversion unit in a time-division manner.

Another object of the present invention is to provide a radio apparatus which modulates a digital baseband signal into an intermediate frequency modulated signal, and demodulates the intermediate frequency received signal into a baseband signal. Variable gain amplifier circuits for keeping the signal level constant, a frequency converter for converting the intermediate frequency after modulation into a high-frequency band, and converting the received high-frequency signal into an intermediate frequency, and transmitting the transmission signal at a specified transmission power. A high-frequency amplifier that amplifies the signal, radiates the radio wave of the output signal of the transmission signal into space, and an antenna that captures the received radio wave that has propagated, and an antenna duplexer that shares the antenna with the transmission and reception frequency. A third frequency converter for frequency-converting an output signal of the high-frequency amplifier on the transmission side to an intermediate frequency; a transmission power level of the third frequency converter; It is a signal switch for switching in time division signal of the received power level of the frequency conversion section achieved by having the signal input side of the gain control unit for controlling the variable gain amplifier circuit.

According to the above means, the signal switch switches the transmission signal and the reception signal in a time-division manner, and converts the transmission power level of the frequency conversion unit for converting the output signal on the transmission side into the intermediate frequency and the frequency conversion unit on the reception side. Are alternately switched and input in a time-division manner. This signal is voltage-converted by a logarithmic amplifier, AD-converted by an AD converter using a sample clock, and input to a gain controller. The gain control unit performs transmission power control and automatic reception gain control through a variable gain amplifier circuit by time division processing using the input AD conversion data. Since the signal switch switches and inputs the transmission signal and the reception signal in a time division manner, one logarithmic amplifier and one AD converter can be used in a time division manner.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention. On the transmitting side, the baseband signal is
, And is input to the frequency converter 28 via the variable gain amplifier 27. The frequency converter 28 converts the frequency of the local oscillator 35 into a high-frequency signal for wireless transmission, amplifies the signal with a high-frequency amplifier 29, and radiates it from the antenna 37 through the antenna duplexer 36 to the air.

The output of the high-frequency amplifier 29 is input to a frequency converter 34 and converted to an intermediate frequency detectable by a logarithmic amplifier. After the converted signal is input to the signal switch 33, it is switched by the switching signal A from the control unit 30 and input to the logarithmic amplification detection circuit 32 to detect the transmission level. The detected voltage is converted into a digital signal by the AD converter 31 switched by the switching signal B from the control unit 30, and the converted digital data is input to the control unit 30. The control unit 30 controls the variable gain amplifier 27 based on the data so that the transmission output level becomes constant.

On the receiving side, the signal received by the antenna 37 is input to the frequency converter 38 via the antenna duplexer 36. The frequency converter 38 is a local oscillator 3
5 and converted into an intermediate frequency, and the converted received signal is input to the signal switch 33 and the variable gain amplifier 39. Similarly to the control on the transmission side, the signal switch 33 switches the signal with the switch signal A from the control unit 30 and the logarithmic amplification detection circuit 32 detects the reception level. The detected voltage is supplied to the control unit 30
Is converted into a digital signal by the AD converter 31 switched by the switching signal B from the controller, and digital data is input to the control unit 30. The control unit 30 controls the variable gain amplifier 39 based on the data so that the signal level input to the demodulation unit 40 becomes constant.

Here, the operation of the signal detection circuit shown in FIG. 2 will be described with reference to a time chart. The switching signal A is a transmission signal obtained by converting the transmission frequency to the same frequency as the reception frequency;
Switch the received signal. In this figure, when the switching signal to the switch 33 is L (LOW), the signal is switched to the reception signal and H (H
At the time of (IGH), it is switched to a transmission signal. After this signal is voltage-converted by the logarithmic amplifier 32, a switching signal B having the same cycle as the switching signal A (sample clock of the AD converter 31)
Is used to perform AD conversion. The control unit 30 performs transmission power control and reception automatic gain control of the obtained AD conversion data by time division processing.

As described above, since the transmission power and the reception power can be detected in a time-division manner by using one logarithmic amplifier 32, the non-linear problem of the power detection circuit using the PIN diode used in the conventional configuration can be obtained. Thus, the shortage of the dynamic range can be eliminated.

[0018]

As described above in detail, according to the structure of the present invention, in order to perform transmission power control with high accuracy, the transmission power level is linearly detected in a wide dynamic range, and the transmission power level and the reception power level are detected. Since the signal converter and the frequency converter for switching the level detection are provided, it is possible to detect the transmission power in a wide dynamic range.
Power control can be performed with higher accuracy than before. Also,
Since the power detection circuit and the AD converter used conventionally are reduced, there is a remarkable effect in reducing the hardware scale.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a time chart illustrating an outline of an operation process of a control unit in FIG. 1;

FIG. 3 is a block diagram illustrating a configuration of a gain control circuit of a conventional wireless device.

FIG. 4 is an example of a detection circuit using a PIN diode.

[Explanation of symbols]

26 modulation section, 27 variable gain amplifier circuit, 28 frequency conversion section, 29 high frequency amplifier, 30 control section, 31 A
D converter, 32 logarithmic amplification detection circuit, 33 signal switcher, 34 frequency converter, 35 local oscillator, 36 antenna duplexer, 37 antenna, 38 frequency converter, 3
9: Variable gain amplifier, 40: Demodulation unit.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04B 1/40 H04B 1/40

Claims (3)

[Claims] 1. A gain control circuit for controlling a gain of a wireless device, comprising: a frequency conversion unit for converting a frequency of an output signal on a transmission side into an intermediate frequency; a transmission power level of the frequency conversion unit and a frequency conversion unit on a reception side. A gain control circuit for a radio, comprising: a signal switching unit for switching a signal of a reception power level in a time-division manner on a signal input side of a gain control unit. 2. A method according to claim 1, further comprising a logarithmic amplification detection circuit for detecting a signal level, and an AD converter for converting a detection voltage into a digital signal, between the signal switch and a signal input side of a gain control unit. The gain control circuit for a wireless device according to claim 1. 3. A modulation / demodulation section for modulating a digital baseband signal into a modulation signal of an intermediate frequency and demodulating a reception signal of the intermediate frequency into a baseband signal. A variable gain amplifier circuit, converts the intermediate frequency after modulation into a high-frequency band, and a frequency conversion unit that converts the received high-frequency signal into an intermediate frequency,
A high-frequency amplifier that amplifies a transmission signal to transmit at a specified transmission power, an antenna that radiates a radio wave of an output signal of the transmission signal to a space, and captures a propagated reception radio wave,
In a wireless device including an antenna duplexer that shares an antenna with a transmission / reception frequency, a third frequency conversion unit that frequency-converts an output signal of the high-frequency amplifier on the transmission side to an intermediate frequency; A signal switch for switching a signal of a transmission power level and a signal of a reception power level of the frequency conversion unit on the reception side in a time division manner is provided on a signal input side of a gain control unit for controlling the variable gain amplifier circuit. transceiver.