JPS586428B2 - automatic channel selection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic channel selection device that automatically performs channel selection operations.

In general, television receivers often select channels by rotating the channel knob.Especially when using continuously variable tuning operations such as when selecting UHF channels, the channel selection operation is cumbersome and cumbersome. there were.

Furthermore, in the case of television receivers equipped with touch-type or remote-control type tuning devices, the tuning operation when changing channels is easy, but the preset tuning operation at the time of initial installation can be cumbersome and inexperienced. This was difficult for amateurs.

The present invention relates to an automatic tuning device designed in view of the above points, and is capable of automating a preset tuning operation by sequentially and automatically storing the tuning voltage of each automatically tuned channel. This provides an automatic channel selection device.

In particular, the present invention provides an automatic channel selection device that can accurately receive television signals that arrive mixed with various interference waves and noise, and that does not malfunction due to noise or the like.

The present invention will be described below according to embodiments shown in the drawings.

FIG. 1 of the drawings is a block diagram showing an example of a television receiver having an automatic channel selection device, where 1 is an antenna, 2 is a tuner, 3 is an intermediate frequency circuit, and 4 is an AF.
T circuit.

5 is a video circuit, 6 is a sync separation circuit, 8 is a deflection circuit, and 8 is a picture tube, and these constitute a normal television receiver.

Here, these include a start/stop circuit 9, a tuning voltage generation circuit 10, a memory circuit 11, a signal discrimination circuit 12,
and a noise skip circuit 13 are added to constitute an automatic channel selection device.

When a search start command (automatic tuning command) is given to the start/stop circuit 9 during preset tuning, a search start pulse is generated from the circuit 9 and supplied to the tuning voltage generation circuit 10.

At this time, the tuning voltage generating circuit 10 generates a sweep voltage or staircase voltage that gradually increases or decreases, and this is supplied as a tuning voltage to the tuning diode of the tuner 2 via the memory circuit 11. Therefore, at this time, the tuner 2 The receiving frequency will be gradually changed.

When the television radio waves of the current channel are received in this way, a television video signal is derived from the intermediate frequency circuit 3, and in conjunction with this, the same signal is derived from the synchronization separation circuit 6 and supplied to the start/stop circuit 9. .

On the other hand, the AFT detection output from the AFT circuit 4 is also supplied to the start/stop circuit 9.

In particular, since the polarity of the AFT detection output voltage changes when the television radio wave is exactly received correctly, this time is detected and the television synchronization signal is derived from the start/stop circuit 9.

The synchronization signal is supplied to a noise skip circuit 13, where it is determined whether or not it is a regular television vertical synchronization signal.

Especially if this is determined to be a legitimate vertical synchronization signal,
At the same time as it is applied to the signal discrimination circuit 12, it is supplied to the tuning voltage generation circuit 10 as a search stop pulse.On the other hand, if it is determined that this is not a synchronization signal but noise, it is supplied to the start/stop circuit 9 as a re-search start pulse. As a result, the same operation as when the above-described first search start command was given is repeated again.

Note that here, the vertical synchronization signal obtained from the noise skip circuit 13 also serves as a search stop pulse.

In this way, a search stop pulse is derived from the noise skip circuit 13, and when it is supplied to the tuning voltage generation circuit 10, the sweep wave (or staircase wave) generation operation is stopped in the generation circuit 10. The voltage is held and supplied to the tuner 2 via the memory circuit 11 as a tuning voltage.

On the other hand, at this time, the vertical synchronization signal derived from the start/stop circuit 9 is supplied to the signal discrimination circuit 12, where it is again discriminated whether or not the signal is a regular television synchronization signal.

The signal discrimination circuit 12 is disclosed in Japanese Patent Application No. 52-515, for example.
As proposed in No. 28 or Japanese Patent Application No. 51-51531, the number of synchronization signals is counted and whether or not a predetermined number of synchronization signals exist during a certain period of time is used to determine whether the signal is a regular television synchronization signal. When it is determined that this is a regular synchronizing signal, a memory command is derived from the signal discriminating circuit 12, and the command is supplied to the memory circuit 11.
The tuning voltage supplied by the controller is memorized.

However, when the pseudo synchronization signal is erroneously derived from the noise skip circuit 13, this signal is detected by the signal discrimination circuit 12.
The circuit 12 generates a re-search start pulse.

This pulse is supplied to the start/stop circuit 9, whereby the same operation as when the above-mentioned first search start command was given is repeated again.

In this way, the same operation is repeated until a true television vertical synchronization signal is derived from the start/stop circuit 9 and the noise skip circuit 13, that is, until correct reception is performed at the tuner 2, and the reception state of a certain channel is accurately achieved. Only then is a memory command issued from the signal discrimination circuit 12, and the tuning voltage at this moment is memorized in the memory circuit 11, and thereafter this memory voltage is supplied from the memory circuit 11 to the tuner 2.

Once the preset tuning operation for a specific channel as described above is performed, if a tuning command is given to this memory circuit 11 by touch or remote control during normal channel selection, the memory circuit 11 will be The memory voltage is supplied to the tuner 2 as a tuning voltage, and this channel is selectively received.

Although only one memory circuit 11 is shown here, in reality, similar memory circuits are provided for the number of preset stations, and a preset tuning operation (automatic selection) of the tuning voltage stored in each memory circuit is performed. Station operations) are performed sequentially by operations similar to those described above.

As described above, according to the automatic tuning device of this embodiment, when a search start command is given during automatic tuning and a search start signal is supplied from the start/stop circuit 9, the tuning voltage generating circuit 10 generates a sweep wave (or Staircase wave) generation operation is started, and the tuning voltage obtained here is applied to the memory circuit 1.
1 to the tuner 2, and the receiving frequency is gradually changed.

In this way, when the search stop signal is derived from the noise skip circuit 13 when receiving television radio waves, etc., the sweep wave generation operation of the tuning voltage generation circuit 10 is temporarily stopped.
Thereafter, the tuning voltage supplied to the tuner 2 is held constant for a certain period of time.

During this time, the signal discrimination circuit 12 discriminates whether the received signal is a regular television signal, and if it is confirmed to be a regular television signal, a memory command is supplied to the memory circuit 11, and at this time, the tuning voltage generation circuit 10
The resulting tuning voltage is stored in the memory circuit 11, and the automatic tuning operation for one station is completed.

On the other hand, when noise is derived from the noise skip circuit 13 or when the signal discrimination circuit 12 determines that it is not a regular television signal, a re-search start signal is supplied to the start/stop circuit 9 and the above operation is repeated again. It is done.

In this way, the memory circuit 11 performs a memory operation, that is, 1
Every time the preset tuning operation for one station is completed, a search start command is given to the start/stop circuit 9 again, and by the same operation as above, the tuning voltage of each station is sequentially memorized in separate memory circuits, and the preset tuning is performed. The operation is complete.

Now, FIG. 2 shows a specific circuit configuration diagram of the noise skip circuit 13, and will be explained according to this diagram.
The circuit consists of an integrating circuit section 14 mainly consisting of resistors R1 and R2 and capacitors C1 and C2, and a transistor Q. ,Q2,Q
3 and a diode D1, etc.;
Furthermore, a synchronization signal amplification section 16 consisting of a transistor Q4, etc.
Here, from the start/stop circuit 9 to the third
Assuming that a normal (negative polarity) television standard signal as shown in FIG.

Here, the first stage transistor Q1 of the noise detection section 15
The base bias voltage of the transistor is set to, for example, about 0.3 volts by the resistor R3tR4tR and the diode D, so as long as a regular vertical synchronization signal is derived, the positive side of this signal is extremely low. Qt is in the cutoff state, and the other transistor Q2
, Qs are also in the cutoff state.
5, no output signal or search stop pulse is derived.

Therefore, at this time, the vertical synchronizing pulse as shown in FIG. 3C is applied to the base of the transistor Q4 via the capacitor C3, and once amplified, a positive vertical synchronizing pulse as shown in FIG. 3D is sent from the collector of the transistor Q4. is derived and supplied to the signal discrimination circuit 12 and also supplied to the tuning voltage generation circuit 10 as a search stop pulse.

On the other hand, when a noise signal as shown, for example, in FIG. 3E is derived from the start/stop circuit 9, it is integrated by the integrating circuit section 14, resulting in a signal as shown in FIG. 3F.

This noise signal has both positive and negative polarity components, and in particular, the positive polarity portion is higher than the conduction level of transistor Q1 (for example, 0.6 volts), so transistor Q1 is turned on each time, and the transistor Q2,
Qs is also turned on at the same time, and a signal as shown in FIG. 3h is derived from the emitter of transistor Q3.

This is returned to the start/stop circuit 9 as a re-search start pulse.

In this way, in this embodiment, it is determined whether the signal obtained from the start/stop circuit 9 is a regular synchronization signal or a noise signal, and the synchronization signal is sent to the signal discrimination circuit 12 and the tuning voltage generation circuit 10. The noise signal is supplied to the start/stop circuit 9 as a re-search start pulse.

According to the automatic channel selection device of the present invention, all the preset channel selection operations, which were conventionally troublesome, are automatically performed, so even an amateur can easily perform them, which is extremely convenient.

Further, according to the automatic channel selection device of the present invention, since a noise skip device is provided that discriminates between a received television synchronization signal and a noise signal, a search stop command is erroneously given to the tuning voltage generation circuit due to the noise signal. In this case, the pseudo synchronization signal that cannot be recognized by the noise skip circuit is of course recognized by the signal recognition circuit.
As a result, it is possible to obtain an automatic channel selection device that does not malfunction due to noise or the like.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of one embodiment of the automatic tuning device of the present invention, Fig. 2 is a circuit configuration diagram of a noise skip circuit used in the same embodiment, and Fig. 3 is a signal diagram of each part of the noise skip circuit. FIG. DESCRIPTION OF SYMBOLS 1... Antenna, 2... Tuner, 3... Intermediate frequency circuit, 4... AFT circuit, 5... Video circuit, 6...
... Synchronous separation circuit, 7. Biting circuit, 8. Picture tube,
9... Start/stop circuit, 10... Tuning voltage generation circuit, 11... Memory one circuit, 12... Signal discrimination circuit, 13... Noise skip circuit, 14... Integrating circuit section, 15... Noise detection section, 16... Synchronization signal amplification section.

Claims (1)

[Claims] 1. A start/stop circuit that detects a search start command for automatic channel selection operation and an incoming television signal and derives a search start signal and a search stop signal, respectively, and a tuning circuit whose operation is controlled by the search start signal and search stop signal. A voltage generation circuit, a memory circuit that stores the tuning voltage obtained from the tuning voltage generation circuit, and a memory circuit that determines whether the incoming television signal is a regular synchronization signal or noise, and when it is noise, causes the start/stop circuit to start searching again. A noise skip circuit that gives a command and the number of synchronization signals obtained from the noise skip circuit are counted, and whether or not a predetermined number of synchronization signals are present within a certain period of time is determined to determine whether or not the signal is a regular television signal. A signal judgment circuit that gives a memory command to the memory circuit when the memory circuit is normal, and gives a re-search start command to the start/stop circuit when the memory circuit is not normal, and means for supplying the tuning voltage obtained from the memory circuit to the tuner. automatic channel selection device.