JPS60217769A - Receiver - Google Patents

Abstract

PURPOSE:To receive both FM stereophonic broadcasting and sound multiplex broadcasting with a receiver, by installing a leaf switch to the drum of a variable condenser and switching an FM demodulator and TV sound multiplex demodulator in accordance with a receiving frequency. CONSTITUTION:A leaf switch 4 is installed to the drum of a variable condenser and the switch 4 is short-circuited when the receiving frequency is 90-108MHz. Since the leaf switch 4 does not operate when the receiving frequency is 76- 90MHz, this receiver outputs an FM multiplex demodulator 3 side. When the receiving frequency becomes 90-108MHz as in the case of TV sound multiplex broadcasting, the leaf switch 4 is short-circuited and a TV sound multiplex demodulator 5 side is outputted by switching a switching circuit 6. Therefore, by making the variable condenser variable, stereophonic reproduction is made when FM stereophonic broadcasting is received and, when TV sound multiplex broadcasting is received, stereophonic reproduction is made in the case of stereophonic broadcasting and duplex reproduction is made in the case of two-language broadcasting.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an FM wideband receiver.

Conventional configuration and its problems In recent years, the number of TV audio multiplex broadcast programs has been increasing.

A conventional receiver will be explained below.

FIG. 1 is a block diagram of a conventional receiver, where 1 is 76~
A front end using a variable capacitor that receives 108 MHz, 2 an intermediate frequency amplifier and detector, and 3 an F'M multiplex demodulator.The receiver configured as above can broadcast 6 to 90 MHz FM. When received, if it is a stereo broadcast, it will be played in stereo. However, 9
When a low band of television (hereinafter referred to as TV) broadcasting of 0 to 108 MHz is received, even in the case of TV audio multiplex broadcasting, since there is no audio multiplex circuit, it can only be reproduced in monaural.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems.If a variable capacitor is varied and an FM stereo broadcast is received, it is played back in stereo.
The purpose of the present invention is to provide a receiver that can reproduce TV audio multiplex broadcasts in stereo if they are received, or in duplex if they are bilingual broadcasts. do.

Structure of the Invention The present invention provides a front-end variable capacitor for receiving FM wideband, which is provided on a rotating drum.
A cam mechanism and a leaf switch that distinguish between MHz and 90 to 108 MHz, an FM multiplex demodulator installed at the output of the detector, a multiplex demodulator for TV audio multiplex broadcasting, and an FM multiplex demodulator when the receiving frequency is 76 to 90 MHz. This is a receiver equipped with a switching circuit on the plex demodulator side that switches the output to the TV audio multiplex demodulator side when the frequency is 90 to 108 MHz, and by switching the output with the leaf switch, FM stereo broadcasting can be made into stereo. TV audio multiplex broadcasts can be played in stereo or in two languages.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 is a block diagram of a receiver according to an embodiment of the present invention, and FIG. 3 is a perspective view of the main parts thereof, and explanations of parts given the same numbers as in FIG. 1 will be omitted. In Figure 2, 4 is a leaf switch whose receiving frequency is 90 to 108 MHz.
Short circuit occurs when .

5 is a TV audio multiplex demodulator, 6 is a switching circuit for switching the output, in FIG. 3, 7 is a variable capacitor, 8 is a drum fixed to the shaft of the variable capacitor, 9 is a cam provided on the outer periphery of the drum, 10 is a The leaf switch is installed in a position linked by cam 9, and the second
Corresponds to 4 in the figure.

The operation of the receiver of this embodiment configured as described above will be described below.

First, when the receiving frequency is 76 to 90 MHz, the leaf switch does not operate, so the receiver outputs the FM multiplex demodulator side. Next, the receiving frequency is 90-10
When the frequency reaches 8 MHz, the leaf switch is short-circuited by the cam 9, the switching circuit 6 is switched, and the receiver is set to T.
V audio multiplex multiplex demodulator side is output.

As described above, according to this embodiment, the receiving frequency is 90~
By installing a leaf switch in the variable capacitor that shorts out at 108 MHz and operating a switching circuit that switches between the FM multiplex demodulator and the TV audio multiplex demodulator, the variable capacitor can be varied to receive FM stereo broadcasts. Then it will play in stereo and the TV
When an audio multiplex broadcast is received, it can be played in stereo if it is a stereo broadcast, or in duplex if it is a bilingual broadcast.

Effects of the Invention The present invention has a receiving frequency of 76 to 90 MHz and 90 to 1 MHz.
A cam mechanism that identifies 08 MHz and a leaf switch are installed on the drum of the variable capacitor, and the receiving frequency is 76 to 9 Q.
FM multiplex demodulator when MHz, 90~
By switching the output to the TV audio multiplex demodulator when the frequency is 108 MHz, you can vary the variable capacitor and receive TV corondos.In the case of audio multiplex broadcasting, you can play it in stereo or duplex. It is possible to provide a receiver with

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional receiver, FIG. 2 is a block diagram of a receiver according to an embodiment of the present invention, and FIG. 3 is a perspective view of the main parts thereof. 4.1o・・・leaf switch, 6・・・・・・
TV audio multiplex demodulator, 6...
Switching circuit, 8...Drum, 9...
··cam.

Claims (1)

[Claims] A front-end variable condenser that receives FM wideband and a 76-9 mounted on the drum that rotates this variable condenser.
a cam mechanism for identifying 01vIH2 and 90-108MH2, and a leaf switch operated by the ξ cam mechanism;
an FM multiplex demodulator provided at the output of the detector;
Using a multiplex demodulator for television audio multiplex broadcasting and the above leaf switch, the reception frequency is 76 to 9.
Receiver 0 equipped with a switching circuit that switches the output to the FM multiplex demodulator side when the reception frequency is 0 MHz and to the television audio multiplex demodulator side when the reception frequency is 90 to 108 MHz.