JPS5833723B2 - Digital channel selection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a channel selection device for a voltage synthesizer type preset all-band television receiver or AM-FM receiver that uses an electronic tuning tuner that generates a tuning voltage through digital processing to achieve tuning. In particular, the present invention relates to a device that automatically switches bands to enable manual tuning, auto sweep, and auto stop tuning.

Conventional voltage synthesizer type TV receivers and AM-FM
In the receiver, the frequency bands of each band are far apart, so it is necessary to select and switch the bands separately.
This inevitably made the operation complicated.

In addition, it was extremely difficult to perform auto-sweep and auto-stop tuning using up or down operation signals to cover all bands.

In view of these points, the present invention provides three bands of VHF low channel, ■F high channel, and UHF, and AM-FM in the case of a voltage synthesizer type television receiver.
In the case of a receiver, it is possible to automatically switch between two bands such as AM and FM, etc., and also automatically sweep all bands continuously to perform auto sweep and auto stop tuning (automatic tuning). ).The present invention provides an improved channel selection device that enables the following.

For this purpose, the present invention provides a clock pulse to a first voltage generating circuit and a pulse obtained by dividing the clock pulse by N to a second voltage generating circuit to generate an analog signal from the first voltage generating circuit. The tuning voltage is input to the tuner, and the tuner band switching is performed using the signal from the second voltage generation circuit, and the first and second voltage generation circuits are operated by the manual tuning operation signal to generate the desired voltage in the tuner. The present invention is characterized in that it is possible to automatically select a desired channel in the band, and furthermore, the clock pulse and the N-divided pulse are stopped using a tuning detection signal from the tuner to perform auto sweep and auto stop channel selection. .

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings.

To explain the case where the present invention is applied to a television receiver in FIG. 1, the channel select switch 3 includes up and down operation switches 3 a and 3 b for auto sweep and auto stop channel selection, and manual channel selection e.g. Four operation switches 3c to 3f are provided, and operation signals from these channel select switches are input to two voltage generation circuits 1 and 2.

These voltage generating circuits 1 and 2 are constructed in exactly the same way as up/down counters 1a and 2a and 1D-A converter lb, respectively.

2b and memories 1c and 2c, and when clock pulses are applied from a clock pulse generator 5 to one voltage generating circuit 1, an analog signal proportional to the number of clock pulses is generated.

In addition, the clock pulses of the clock pulse generator 5 are
The pulses are input to a frequency divider circuit 6 corresponding to the number of bands, and the pulses frequency-divided by three are given to the other voltage generating circuit 2, which generates a signal proportional to the number of pulses. ing.

The signals from these voltage generating circuits 1 and 2 are filtered by low-pass filters 7 and 8, respectively, to remove harmonic components. As a result, the signals from the low-pass filters 7 and 7 become sawtooth waveforms as shown in Fig. 2a, and are low-pass filters. The signal from the filter 8 has a voltage curve whose slope is 1/3 that of the signal a, as shown in FIG. 2b.

As shown in Figure 2a, in signal a, point B is at a position slightly past the 3rd channel of television broadcast waves, and point C is also at a position slightly before the 4th channel. section is VHF low channel, C
-D section is VHF high channel, D-E section is VHF channel.
A UHF tuner 17 and a VHF tuner 18 are used as tuning voltages for each band of HF via a switch circuit 9.
is input.

The signals c and d from the former 10.11 of the three voltage converters 10 to 12 are subtracted by the subtracter 13 to become a signal like e in Fig. 2. , this signal e is input to the switch circuit 9.

Therefore, the tuning voltage signal to the tuners 17 and 18 becomes zero only in the section B-C, as shown in f in Fig. Other communication signals etc. are made impossible to select.

Further, the signal g from the voltage comparator 12 is input to the power supply switching circuit 15, and the signal c2g from the voltage comparators 10 and 12 is input to the switching diode switching circuit 16 via the subtracter 14.

The power supply switching circuit 15 outputs 10B depending on the L and H of the signal g.
The power supply is VHF low, and the high channel is VHF
The tuner 18 and the UHF tuner 17 each have a receiver, and the switching diode switching circuit 16 is configured to switch and provide the UHF band to the UHF tuner 17 which has a receiver.
By generating a signal such as VHF and applying it to the VHF tuner 18, the VHF tuner 18 resonates at a lower frequency.
A built-in switching diode (not shown) is switched to enable selection of the HF low channel and the VHF high channel that resonates at a high frequency.

Furthermore, when performing auto sweep and auto stop tuning, tuning detection is performed using the DC output voltage (so-called S curve output) from the FM detector 19 of the VHF tuner 18, and the auto sweep control circuit uses the detection power. 4 is activated, and the operation of the clock pulse generator 5 is stopped based on the signal from this circuit 4.

Further, the operation of the auto sweep control circuit 4 is controlled by a signal from the channel select switch 3, and the operation of the clock pulse generator 5 is restarted.

As a result, during manual channel selection, when any one of the four operation switches 3C to 3f of the channel select switch 30 is operated, the binary code from the memories 1c and 2c sets the counter contents of the up and down counters 1a and 2a. However, the set analog signals are extracted from the voltage generation circuits 1 and 2 by the clock pulses from the clock pulse generator 5 arriving at the same time and the pulses obtained by frequency-dividing the clock pulses by three.

Then, the power supply switching circuit 15 and the switching diode switching circuit 16 are activated by the signal from the voltage generation circuit 2, and band switching is performed, and the tuner 17 and 18 are set to VI
(You are now in a state where you can select the desired one of the three bands: F low channel, VHF high channel, and UHF.

Also, at this time, the tuning voltage of the desired channel by the signal from the voltage generating circuit 1 is input to the tuners 17 and 18, so that the desired channel of the desired band can be automatically selected.

Next, when the up or down operation switch 3a or 3b of the channel select switch 3 is operated to select auto sweep or auto stop, the operation signal is transmitted to the voltage generation circuits 1 and 2 and the auto sweep control circuit 4.
A clock pulse and a pulse whose frequency is divided by three are input to voltage generating circuits 1 and 2, respectively.

Therefore, analog signals for tuning and band switching are continuously provided from the voltage generating circuits 1 and 2.
The receiver's auto sweep will be disabled.

Once a broadcast wave is received, the FM detector 19
The duck signal enters the auto-sweep control circuit 4, clock pulses, etc. are no longer output, and the channel selection operation is automatically stopped.

As described above, in the present invention, an analog signal is generated by a pulse obtained by dividing a clock pulse by N, and the band filters are dynamically switched and tuned based on the analog signal, thereby eliminating the need for the conventional band switching operation.

In addition, by controlling the operation of the clock pulse generator, it is possible to continuously perform auto sweep and auto stop tuning for all bands, and furthermore, it is possible to instantly select any band from the VHF low channel to the UHF channel. can be stored in memory or recalled.

It goes without saying that the present invention can be applied not only to the television receiver shown in the embodiment but also to an AM-FM receiver in exactly the same manner.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a channel selection device according to the present invention, and FIG. 2 is a waveform diagram illustrating the operation. 1.2... Voltage generation circuit, 3... Channel select switch, 4... Auto sweep control circuit, 5... Clock pulse generator, 6
...3 frequency divider circuit, 7.8 ... low pass filter, 9 ... switch circuit, 10, 11,
12...Voltage comparator, 13.14...
...Subtractor, 15...Power switching circuit, 16
...Switching diode switching circuit, 17
...UHF tuner, 18...VHF
Tuner, 19...FM detector.

Claims (1)

[Claims] 1. A clock pulse is given to a first voltage generation circuit, and a pulse obtained by dividing the clock pulse by N is given to a second voltage generation circuit to generate an analog signal from the first voltage generation circuit. band switching signal generating means including a plurality of voltage comparators that are input to the tuner as a tuning voltage and generate band switching signals for the tuner using signals from the second voltage generating circuit; and an output of the band switching signal generating means. means for giving the output from the first voltage generating circuit a voltage change width corresponding to each band, the tuning operation signal operates the first and second voltage generating circuits, and the tuner operates the desired band. A digital channel selection device characterized by being able to continuously select desired broadcast waves. 2. A clock pulse is given to the first voltage generation circuit, and a pulse obtained by dividing the clock pulse by N is given to the 20th voltage generation circuit, and the analog signal from the first voltage generation circuit is inputted to the tuner as a tuning voltage. , band switching signal generating means including a plurality of voltage comparators that generate band switching signals for the tuner using signals from the second voltage generating circuit; and a first voltage generating circuit using the output of the band switching signal generating means. the clock pulse and a pulse obtained by dividing the clock pulse by N to the first and second voltage generating circuits according to a tuning operation signal; The tuner continuously tunes a desired broadcast wave of a desired band, and the clock pulse and the N-divided pulse are transmitted to the first and second channels by a signal from a tuning detection circuit provided in the tuner. A digital channel selection device characterized in that it is possible to continuously automatically select a desired broadcast wave of a desired band by stopping application of voltage to a voltage generation circuit.