JPH03265221A - Receiver - Google Patents

Abstract

PURPOSE:To easily attain an optimum reception state by applying fuzzy inference operation based on an electric field strength detection signal and a noise detection signal extracted from a reception circuit and outputting a control signal based on the result to the reception circuit. CONSTITUTION:A reception level signal S and a noise level signal N are inputted to a fuzzy control section 30 to discriminate the reception state and outputs a control signal SS to an S/N control circuit. A separation control circuit 53 starts its operation when the level of the signal SS reaches <=45dB/muV to change the separation continuously and reaches the monaural mode when the level of the signal SS reaches 25dB/muV. A frequency characteristic control circuit 54 starts the operation when the level of the signal SS reaches 35dB/muV so as to increase the attenuation at the high frequency band of the input signal until the level of the signal SS reaches 15dB/muV. A mute driver 51 uses a mute driving signal MD to operate a soft mute circuit 52 when the level of the signal SS reaches 25dB/muV to increase the attenuation input terminal according to the reception signal. Thus, while the S/N is kept constant as it is, the output is obtained.

Description

[Detailed description of the invention] [Industrial application field] TECHNICAL FIELD This invention relates to receivers, and more particularly to radio receivers.

[Conventional technology]

FIG. 3 shows a detailed block diagram of a conventional receiver.

The receiver can be roughly divided into a receiving system and a receiving system, and is connected to the output end of the receiving system, and adjusts the signal-to-noise ratio (
(hereinafter referred to as S/N) is kept almost constant and output
/'N control circuit 500.

The reception system is connected to the antenna ANT and receives RF (Radio
o F+equenc7) A receiving circuit 100 that processes signal A and outputs received signal B, and a receiving level detection circuit 102 that detects a receiving level signal (for example, an S meter level signal) corresponding to electric field strength and outputs a receiving level signal.
have. The receiving circuit 100 includes a front end, an intermediate frequency amplifier, a wave detector, etc. (not shown). The level detection circuit 102 detects the received level signal S from, for example, an output signal after the intermediate frequency amplifier or detector. The S/N control circuit 500 generates a mute drive signal M based on the reception level signal S.
A mute driver 501 that generates and outputs a signal D, and a soft mute circuit 502 that continuously attenuates the output level of an input signal based on a mute drive signal MD and outputs the same.
and a separation control circuit 5 that includes a stereo demodulation circuit (not shown) and continuously changes the separation of left and right channel signals based on the received level signal S.
03, and a frequency characteristic control circuit 504 that continuously changes the frequency characteristic of the input signal based on the received level signal S and outputs the same.

Next, the operation will be explained.

In the receiving system, a receiving circuit 100 takes in an RF signal A from a connected antenna ANT and outputs a received signal B. For example, the reception level detection circuit 102 detects the reception level from the output signal of a subsequent stage of a detector (not shown) of the reception circuit 100, and outputs the reception level signal S.

The separation control circuit 503 controls the reception signal S
level is a predetermined first value, for example, 45 dB/μV
When the voltage is below 25 dB/μV, it starts operating and continuously changes the separation of both left and right channels, and when it reaches 25 dB/μV, it operates in monaural mode.

The frequency characteristic control circuit 504 starts operating when the received level signal S reaches a predetermined second value, for example, 35 dB/'μV, and the amount of attenuation of the high frequency range of the input signal increases until it reaches 15 dB/μV. Do it like this.

When the reception level signal S reaches a predetermined third value, for example, 256B/μV, the mute driver 501 operates the soft mute circuit 502 using the mute drive signal MD, and increases the amount of attenuation in accordance with the reception level signal S1. let

In this way, the S/N control circuit 500 can maintain a constant S/N based on the received level signal S as shown in FIG. In FIG. 4, curve a represents the soft mute circuit 502, separation control circuit 503, and frequency characteristic control circuit 50.
4 shows the input/output characteristics when all of them are inactive. The curve shows the input/output characteristics when only the frequency characteristic control circuit 504 operates. Curve C shows the input/output characteristics when only separation control circuit 503 operates. Curve d shows the input/output characteristics when both frequency characteristic control circuit 504 and separation control circuit 503 are operated. Curve e shows the input/output characteristics when only soft mute circuit 502 operates.

A curve f shows the input/output characteristics when the soft mute circuit 502, separation control circuit 503, and frequency characteristic control circuit 504 are all in operation.

[Problem to be solved by the invention]

In the conventional stereo receiver described above, only the reception level signal S is used as a control signal for the S/N control circuit. Therefore, no matter how large the noise is, there is a problem in that the noise level is not taken into account and a good S/N ratio cannot be maintained.

In view of the above problems, an object of the present invention is to provide a receiver that can maintain good reception conditions.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a receiving circuit that demodulates and regenerates a received RF signal, performs fuzzy inference calculation based on a field strength detection signal and a noise detection signal extracted from the receiving circuit, and performs fuzzy inference calculation based on the calculation result. The apparatus is configured to include a fuzzy control section that outputs a control signal to the receiving circuit.

[Effect]

According to the present invention, the fuzzy control section performs fuzzy inference based on the field strength detection signal and noise detection signal extracted from the receiving circuit, comprehensively determines the reception state, and outputs a control signal.

Therefore, the reception system can perform more accurate reception control based on the control signal.

〔Example〕

Next, an embodiment of the present invention will be described with reference to FIG.

The receiver 10 is roughly divided into a receiving system connected to the ANT, a fuzzy control section 30 that outputs a control signal for controlling an S/N control circuit (to be described later), and an S/N system connected to the output end of the receiving system. N control circuit 50.

The reception system includes a reception circuit 11 that processes the RF signal A from the antenna ANT and outputs a reception signal B, and a reception level signal (for example, an S meter level signal) corresponding to the electric field strength.
It has a reception level detection circuit 12 that detects the signal level and outputs a reception level signal S, and a noise level detection circuit 13 that detects the signal level of noise included in the reception output signal C and outputs a noise level signal N. . The receiving circuit 11 includes a front end, an intermediate frequency amplifier, a wave detector, etc. (not shown). The reception level detection circuit 12 detects the reception level signal S, for example, from the output signal of the latter stage of the intermediate frequency amplifier or detector. The noise level detection circuit 3 includes, for example, a bypass filter (not shown), and detects the noise level based on the output signal level of the bypass filter.

The fuzzy control unit 30 has a CPU, and uses a built-in program to control the S/N control circuit 5 based on the reception level signal S and the noise level signal N of the reception system.
A control signal SS for controlling 0 is output.

The S/N control circuit 50 generates a mute drive signal MD based on the control signal SS from the fuzzy control section 30.
a mute driver 51 that outputs a mute drive signal MD, a soft mute circuit 52 that continuously attenuates the signal level of the received output signal C based on a mute drive signal MD, and outputs it as an output signal; Perform signal separation control to output signal F
and a frequency characteristic control circuit that continuously changes the frequency characteristic of the output signal F and outputs it as the output signal G based on the control signal SS.

The soft mute circuit 52 is, for example, a voltage controlled amplifier (
Unlike ordinary mute circuits, which are configured with VCA) and have a custom-made step-function attenuation curve (that is, a characteristic that rapidly reduces the signal level), it is possible to have a gentle attenuation characteristic curve. be.

The separation control circuit 53 includes a stereo demodulation circuit (not shown), and operates to continuously change the separation of the left and right channel signals based on the control signal SS.

The frequency characteristic control circuit 54 controls the amount of high-frequency attenuation of the input signal based on the control signal SS.

The mute driver 51 generates a mute drive signal MD based on the control signal SS, and controls the soft mute circuit 52 using this mute drive signal MD.

Next, the operation will be explained.

In the receiving system, the receiving circuit 11 processes the RF signal A from the antenna ANT and outputs the received signal B. The reception level detection circuit 12 detects a reception level from, for example, an output signal of a subsequent stage of a detector (not shown) of the first reception circuit 11, and outputs a reception level signal S. The noise level detection circuit 13 detects the level of a noise signal included in the received signal B, and outputs a noise level signal N.

A received level signal S and a noise level signal N are input to the fuzzy control section 30. The fuzzy control unit 30 is
The reception state is determined based on those signals, and the control signal SS is sent to the S/N control circuit 5 based on the determination result.
Output to 0.

The separation control circuit 53 receives a control signal SS
level is a predetermined first value, e.g. 45 dB/μV
When it reaches 25 dB/μ■, it starts operating and changes the ratio continuously, and when it reaches 25 dB/μ■, it starts operating in monaural mode.

The frequency characteristic control circuit 54 starts operating when the control signal SS reaches a predetermined second value, for example, 35 dB/μV, and increases the amount of attenuation of the high frequency range of the input signal until it reaches 15 dB/μV. do.

When the control signal SS reaches a predetermined third value, for example, 25 dB/μV, the mute driver 5 operates the soft mute circuit 52 using the mute drive signal MD, and attenuates the soft mute circuit 52 according to the first reception level signal Sl. Increase quantity.

In this manner, the S/N control circuit 50 is able to output the input signal while keeping the S/'N of the input signal constant, as shown in FIG. 5, based on the control signal SS.

As explained above, according to this embodiment, even when the receiving system is switched, the S/N control circuit operates according to the receiving state of the switched receiving system, so the optimum S/N is always maintained. It becomes possible.

In the above embodiments, only the case of a stereo receiver has been described, but the present invention can also be applied to a monaural receiver by eliminating the function of the separation control circuit. Furthermore, although only the control of the S/N control circuit has been described above, it can also be used to control other circuits within the receiving circuit. For example, automatic gain control (AGC) of the high frequency amplifier circuit in the front end
It is also possible to configure the system to control more accurately.

〔Effect of the invention〕

According to the present invention, since the receiving circuit can be controlled by performing fuzzy inference calculations based on the field strength detection signal and the noise detection signal extracted from the receiving circuit, it is possible to easily maintain an optimal receiving state. It becomes possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a receiver according to the present invention. FIG. 2 is an explanatory diagram of a conventional receiver. FIG. 3 is an explanatory diagram of the operation of an S/N control circuit. 10... Receiver 11... Receiving circuit 12... Reception level detection circuit 13... Noise level detection circuit 30... Fuzzy control section 50... S/N control circuit 51... Mute driver 52...Soft mute circuit 53...Separation control circuit 54...
Frequency characteristic control circuit A...RF multiplied signal NT...Antenna B...Received signal, F, G...Output signal N...Noise level signal S...Received level signal SS... Control signal

Claims (1)

[Claims] 1. A receiving circuit that demodulates and reproduces a received RF signal, and performs fuzzy inference calculations based on a field strength detection signal and a noise detection signal extracted from the receiving circuit, and generates a control signal based on the calculation result. A receiver comprising: a fuzzy control section that outputs to the receiving circuit. 2. The receiver according to claim 1, wherein the receiver includes an SN ratio control circuit that maintains the SN ratio of the received signal substantially constant in response to a control signal based on the result of the fuzzy inference calculation. Receiving machine. 3. The receiver according to claim 2, wherein the receiver is a receiver capable of stereo reproduction, and the SN ratio control circuit operates when the value of the control signal becomes lower than a first threshold. a separation control circuit that continuously changes the separation of channel signals, and operates when the control signal is lower than the first threshold and below a second threshold within the separation control range; a frequency characteristic control circuit that continuously changes and outputs the frequency characteristic of a received signal; and a frequency characteristic control circuit that operates when the control signal falls below a third threshold value that is lower than the second value to continuously change the received signal level. A receiver comprising: variable attenuation means for attenuating and outputting the output.