JPS62277Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a frequency display device for a television receiver.

Conventionally, in a television tuner for audio multiplex broadcasting, when tuning an audio signal to a preset channel, tuning was done while watching a frequency meter.

This invention aims to provide a frequency display device for television receivers that eliminates the need for a conventional frequency meter by adding a rough frequency display function to the display section of the channel corresponding to the receiving station. purpose.

An example of this invention is shown below in Figures 1 and 2.
This will be explained in detail with reference to the drawings.

Reference numeral 1 denotes a front end section to which an input from an antenna is supplied, and includes a tuning circuit that employs an electronic tuning system consisting of, for example, a variable capacitance diode, and a frequency mixing circuit connected to a local oscillation section 2. ing. The tuning circuit and the local oscillator 2 of the front end section 1 are supplied with channels 1 to 1 having the characteristics shown in FIG. 2 from the voltage generating section 3, respectively.
A tuning voltage corresponding to n is selectively supplied. This voltage generating section 3 consists of a channel select switch and a tuning voltage generating volume linked to the channel select switch, and by varying this and applying it to the local oscillating section 2 and the tuning circuit, the reception frequency band is determined. Ru.

Then, the front end section 1 separates the audio signal into an audio signal and a video signal and extracts the audio signal using a so-called split carrier method. The extracted audio signal is independently amplified via an intermediate frequency amplifier circuit 4, then detected via a detection circuit 5, and finally extracted as an audio output. In the detection circuit 5,
A tuning indicator 6 is provided,
Show synchronization status.

On the other hand, the output of the detection circuit 5 and the tuning voltage of the voltage generating section 3 are also controlled by the first control circuit 7.
are supplied respectively. The output of the voltage generator 3 and the output of the first control circuit 7 are selectively supplied to the second control circuit 9 via the changeover switch 8. That is, when the changeover switch 8 is switched to the contact a side, the tuning voltage of the voltage generator 3 is directly supplied to the second control circuit 9. The second control circuit 9 adjusts the tuning voltage from 1 to
It is divided into voltages corresponding to the frequency of the n channel and outputted, and is supplied to the channel and frequency display unit 10 as a drive signal. The display section 10 is provided with, for example, a light-emitting display section for each channel 1 to n, and one of them is driven by the output of the second control circuit 9. Therefore, by varying the tuning voltage, the drive state of the display section changes from 1 to n, and it is possible to determine which frequency band the display section is tuned to based on the channel number.

That is, it can essentially be used as a frequency display. When the receiver is accurately tuned to the receiving station, the above-mentioned tuning indicator 6 emits light.

On the other hand, when the changeover switch 8 is switched to the contact b side, the tuning voltage is supplied to the second control circuit 9 via the first control circuit 7. In this case, the channel selector switches 1 to n of the voltage generating section 5 and the channel display sections 1 to n of the display section 9
Since n matches, the display becomes a channel. If a station is not being received, the first control circuit 7 is controlled by the signal from the detection circuit 5 so as not to supply voltage to the second control circuit 9. Therefore, the display section 10 does not light up. At this time, when channel select switches 1 to n are pressed, whether or not a channel is displayed determines whether or not a station is stored in the channel.

As described above, according to this invention, a rough frequency display function is given to the display section of the channel corresponding to the receiving station, so there is no need for a conventional frequency meter (dial mechanism, etc.) Both displays are possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of this invention.
FIG. 2 is a characteristic diagram for explaining the operation. 1...Front end section, 3...Voltage generation section,
5...Detection circuit, 7...First control circuit, 8...
Changeover switch, 9...Second control circuit, 10...
Channel and frequency display.

Claims (1)

[Scope of utility model registration request] A voltage generating section determines the receiving frequency band by applying a tuning voltage to the front end section, and the output of this voltage generating section and the detection output of the audio signal line are respectively input, and when a station is being received, the above tuning is performed. A first control circuit that outputs a voltage and does not generate an output under the control of the detection output when the other station is not being received, and the output of the first control circuit or the voltage generator is input. , a second control circuit that divides their outputs into voltages corresponding to frequencies of the plurality of channels, and a channel and frequency driven by the output of the second control circuit to display the channels and their corresponding frequencies. A frequency display device for a television receiver, comprising a display section.