JPS6093841A - Reception circuit - Google Patents

Abstract

PURPOSE:To use in common a reception circuit at a mixer and succeeding stages by inputting an output of plural mixers converting plural reception signals into a single intermediate frequency to a single intermediate frequency circuit. CONSTITUTION:Antennas 1, 1', RF units 2, 2' and mixers 3, 3' constitute the 1st and 2nd pre-stage reception circuits, which input selected local signals fL, fL' to the local side of the mixers 3, 3' so as to convert a desired input signal fi into an intermediate frequency. Other input signal fi' converted into the intermediate frequency is outputted to an intermediate frequency circuit 6 via an amplifier 4'. The intermediate frequency circuit 6 outputs the inputted input signals fi, fi' to the reception circuit of the post-stage via an output terminal 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a receiving circuit, and more particularly to a receiving circuit capable of monitoring a plurality of received signals.

Conventionally, when operating a wireless communication device, etc., multiple reception signals are listened to, and if necessary, one of the multiple reception signals (IT signal) may be taken out.Usually, this pond operation (hereinafter) is called a multi-signal monitor. ) prepares a plurality of receivers and selectively monitors the desired signal by operating the AF dyne control or turning on/off the output to the speaker as appropriate.

In the multi-signal monitor described above, it is necessary to prepare a plurality of receivers, which causes unreasonable problems such as an increase in the space for placing the receivers and a decrease in operability.

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a receiving circuit provided with a common intermediate frequency circuit for a plurality of received signals.

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

In the figure, 1.1' is an antenna, 2 and 2' are an RF unit, 3.3' is a mixer, 4 and 4' are amplifiers, and 5°5' is a variable resistor. Antenna 1, RF unit 2
, mixer 3 constitutes a first front-stage receiving circuit.

The first front-stage receiving circuit converts the selected roll signal fL into a desired input signal flt-intermediate frequency which is input to the local side of the mixer 3. Input signal f1 converted to intermediate frequency
is outputted to the subsequent intermediate frequency circuit 6 via the amplifier 4. Similarly, antenna l', PF unit 2', mixer 3'
The second pre-amplifier circuit constituted by inputs the selected other local signal f'L to the local side of the mixer 3' and converts the other input signal fI' into an intermediate frequency. The other input signal 1i converted to an intermediate frequency is outputted to an intermediate frequency circuit 6 via an amplifier 4/. The intermediate frequency circuit 6 outputs the input signal f+ and other input signals fi via an output terminal 7 to a subsequent receiving circuit.

For example, 434.56 MHz and 43 MHz in the above receiving circuit.
When you want to intercept the desired radio wave of 4.88 MHz, adjust the local signal fL to intercept the desired radio wave of 434.56.
MHz is received by the first front-stage receiving circuit. In addition, the local signal f'L is adjusted and the other desired radio wave is 434.88MH.
z is received by the second front-stage receiving circuit. 4 34.56 MHz and 434 MHz via a single intermediate frequency circuit 6.
An audio signal related to 88 MHz is output from the speaker.

When one variable resistor 5 is operated to attenuate or cut off the audio signal related to 434.56 MHz, the result is 434.88 MHz.
Audio signals related to MHz can be monitored.

The receiving circuit according to the present invention includes a plurality of receivers (a plurality of mixers that convert N signals into a single intermediate frequency signal, and a single intermediate frequency circuit that receives the intermediate frequency output from the plurality of mixers). Because of its configuration, the receiver circuit after the mixer can be shared.For this reason, when you want to intercept multiple received signals, there is no need to install multiple receivers, making it easy to operate with just one receiver. It is expected to improve the space factor related to the installation location.

[Brief explanation of drawings]

The figure is a block diagram of a receiving circuit according to the present invention. In the figure, 1, 1' are antennas, 2, 2' are RF units, 3, 3' are mixers, 4.4' are amplifiers, 5, 5
' is a variable resistor, and 6 is an intermediate frequency circuit. Patent applicant Yaesu Musen Co., Ltd.

Claims (1)

[Claims] 1. A plurality of mixers that convert a plurality of received signals into a single intermediate frequency, and a single intermediate frequency circuit that receives the intermediate frequencies output from the plurality of mixers, and A receiving circuit characterized in that it is configured to monitor a received signal.