JPS6121010B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a tuning device using an electronic tuner, and particularly to an electronic tuning type tuning device with new functions added.

A conventional preset electronic tuning type tuning device generally has a configuration as shown in FIG. 1, for example. In the figure, 1 is a ring IC, which includes a clock oscillator OSC, a ring counter RC, an audio muting circuit MU, and a band switch mechanism BSM. 2 ₁ , 2 ₂ , . . . 2n are 2N channel selection buttons operated by the user. Now, when the user presses the button ₂₂ , the voltage stabilized at around 30 volts by the Zener diode 8 passes through the variable tuning resistor ₄₂ and the tuning button ₂₂ to the clock oscillator OSC of the logic IC1. Activate. The output of the clock oscillator OSC sequentially activates the ring counter RC and the transistors 6 ₁ , 6
_{2. Apply on-pulses to the bases of 2} , . . . sequentially. There, transistor ₆₂ turns on, its collector potential drops to almost 0 volts, and button 22
Since the potential of the clock oscillator OSC also drops to almost 0 volts, the clock oscillator OSC stops operating. As a result, ring counter RC stops providing an on pulse to the base of transistor ₆₂ . Since the above operation is performed almost instantaneously, the user does not need to keep pressing the channel selection button ₂₂ , and the operation is similar to instantaneous touch channel selection. transistor 6 ₂
When turned on, the diode ₅₂ is turned on (the other diodes are turned off), and the tuning voltage of the tuning variable resistor ₄₂ is supplied to the electronic tuner 10 via the diode ₅₂ and the conductor 9. During this time, the channel indicator lamp ₃₂ lights up. switch 7 ₁ , 7 ₂ ,
..., 7n is a switch for switching the TV band to low range, high range and ultra short wave, and the low range terminal L
When it is in the position, the band switch mechanism
The BSM sends an output corresponding to the low frequency band to the band switching mechanism 11 of the electronic tuner 10, and when located at the high frequency terminal H or ultra high frequency terminal U, when those terminals become 0 volts, the high frequency band changes, respectively. Alternatively, output corresponding to the extremely high frequency band is sent to the electronic tuner 10. Therefore, in the case shown, the H terminal of switch ₇₂ becomes almost 0 volts through transistor ₆₂ , so that the band
The switch mechanism section BSM sends an output corresponding to the high frequency band to the band switching mechanism 11 of the electronic tuner 10.

As mentioned above, electronic tuning type tuning devices are much easier to tune than mechanical tuning type tuning devices. However, in the former case, it is possible to select a channel almost instantly. Therefore, if the program the user wants is being broadcast at the same time from different stations, teeth,
It has the advantage of being able to switch channels relatively easily by pressing the channel selection button.

However, given the current situation where many users frequently switch channels when their desired programs overlap, there is a potential for a device that can automatically switch channels. The demand is considered to be very strong. Therefore, the present invention utilizes the above-mentioned features of an electronically tuned tuning device to automatically switch any plurality of channels at any time and at any ratio, and to switch to a desired channel among them as necessary. It is an object of the present invention to provide a channel selection device that can maintain switching and eliminate unpleasant noise during switching.

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 2 is a block diagram showing an embodiment of the present invention. In this figure, parts corresponding to those in FIG. 1 are given the same reference numerals, and the MCS is a main channel selection circuit having the same configuration as that shown in FIG. 1. The SCS is a sub-channel selection circuit that has a tuning function independent of the main channel selection circuit MCS, and in this example, a continuous variable resistor 12 is used for the tuning voltage, and it also has a band changeover switch 13. ing. MDS is a mode selection circuit.
The switch 14 allows selection of either the main channel mode, the sub-channel mode or the alternating mode. Mode switch 14
According to the selected mode, the selection switch circuit
The SSW and the band switch circuit BSW alternately take out the main channel, the sub-channel, or both, and send the tuning voltage to the electronic tuner 10, the TV
(TV) Provides band information. That is, when the mode switch 14 is at the main channel position M, the electronic tuner 10 is operated by the main channel selection circuit MCS, and when the mode switch 14 is at the sub-channel position S, the electronic tuner 10 is operated by the main channel selection circuit MCS. Works with circuit SCS. When the mode switch 14 is in the alternating position A, the electronic tuner 10 operates alternately with the main channel selection circuit MCS and the sub channel selection circuit SCS, and the switching time and duty are controlled by the variable resistor 15.

Note that CPG is a clock pulse generation circuit.
When pulses are generated at regular intervals and these clock pulses drive the clock oscillator OSC shown in Figure 1, the ring counter RC in logic IC1 sends out pulses in sequence, so all channels are automatically switched in sequence. I'm going to go.

FIG. 3 is a detailed circuit diagram showing the block diagram of FIG. 2 more specifically, and parts corresponding to those in FIG. 2 are given the same reference numerals. The operation of this circuit is roughly as follows.

First, when the mode switch 14 of the mode selection circuit MDS is set to the main channel position M, the transistors 21 and 23 of the mode selection circuit MDS are turned on.
20 and 22 are turned off, and the tuning voltage to the electronic tuner 10 is applied via the diode 24 and the conductor 9 from the main channel tuning circuit MCS. For example, if the tuning button ₂₂ is pressed, a tuning voltage determined by the tuning variable resistor ₄₂ is applied through the diode ₅₂ , and the corresponding channel is selected. Also, for the TV band, transistor 6
Since band switch ₇₂ is on, it is determined by band switch ₇₂ . That is, the band switch circuit BSW has a band switch circuit (lower circuit) and an extremely high frequency band switch circuit (upper circuit), and in this case, the transistor 31 of the lower high frequency band switch circuit is turned on. Since the diode 38 is also turned on, the band switch mechanism BSM of the logic IC 1 and the switch ₇₂ are connected.

On the other hand, transistor 2 of the mode selection circuit MDS
2 collector voltage is band switch circuit BSW
transistors 28 and 33 are turned on, and transistors 29 and 34 are turned off. Therefore, when the band selection switch 13 of the sub-channel selection circuit SCS is in the position shown in the figure, the transistor 30 is turned on, and therefore the diode 37 is turned off. become a state. Also, even if the band selection switch 13 is set to the H terminal position,
Diode 39 is also turned off.

Therefore, the band switch mechanism BSM of the logic IC 1 and the band changeover switch 13 of the sub-channel selection circuit SCS are disconnected, and the switch 13
position is ignored. In this way, the mode
When the switch 14 is in the M position, the sub channel selection circuit SCS is completely ignored, and its operation is no different from that of a conventional channel selection device.

Next, when the mode switch 14 of the mode selection circuit MDS is set to the sub-channel position S, the transistor 20 of the mode selection circuit MDS,
22 is on and 21 and 23 are off, the tuning voltage is determined by the tuning variable resistor 12 of the sub-channel tuning circuit SCS, and is applied to the electronic tuner 10 via the diode 25 and the conductor 9. At the same time, the collector voltage of the transistor 21 of the mode selection circuit MDS is applied to the band switch circuit BSW, turning on its transistors 29 and 34 and turning off its transistors 30 and 35, so that the diode 37 or 39 is connected to the subchannel selection circuit. Station circuit SCS
When the band changeover switch 13 is at the U or H terminal position, it is turned on, and the operation of the band switch mechanism BSM of the logic IC 1 is determined by the position of the band changeover switch 13. on the other hand,
Since the diodes 36 and 38 are turned off, when the mode switch 14 is in the S position, the main channel selection circuit MCS is completely ignored.

Furthermore, when the mode switch 14 is set to the alternating position A, the mode selection circuit MDS becomes an unstable multivibrator and repeats on and off, so the electronic tuner 10 has a main channel selection circuit MCS.
and the output of the sub channel selection circuit SCS are applied alternately to automatically switch between the main channel and the sub channel. The switching time and duty of the main channel and sub-channel can be controlled by the user by changing the variable resistor 15 that determines the time constant of the mode selection circuit MDS. It is possible to do so.

In addition, since a pulse can be obtained from the terminal 40 of the mode selection circuit MDS every time the main channel and sub channel are switched, this can be obtained from the logic IC1.
In addition to the audio circuit AF, it is possible to eliminate unpleasant switching noises via the audio muting circuit MU inside. In the illustrated example, the audio muting circuit MU is configured within the logic IC 1 and is operated using negative pulses, but other methods are of course possible. Logic IC for audio muting circuit MU
1, a pulse is obtained from the clock oscillator OSC each time the channel is switched even during normal operation, that is, in the main channel mode, so that noise caused by channel switching can be avoided.

In the example shown in the figure, the clock pulse generator circuit CPG consists of an unstable multivibrator.
When switch 16 is closed, positive pulses are obtained through the diode at regular intervals, so this logic
By controlling the clock oscillator OSC of IC1, it is possible to sequentially tune all of the main channels at regular intervals. In this way, when the switch 16 is closed, sequential feeding of the main channels starts, but if the switch 16 is not turned off, sequential feeding will continue indefinitely. You can also stop this. Alternatively, a pulse counter may be used to count the number of pulses required to perform forward feeding of all channels an integral number of times, and then stop the forward feeding pulses.

As explained above, by using the present invention, not only can it be used as a normal TV, but it is also possible to automatically switch and receive channel A and channel B at any duty and at any interval using a single electronic tuner. For example, it is very convenient to watch a movie program and occasionally catch a glimpse of the progress of a baseball game being broadcast at the same time without requiring any manual intervention. If the baseball program you are currently watching becomes interesting, you can watch the baseball program continuously by simply switching the mode switch from the police box to the subchannel. If this mode switch does not have a secondary channel position, it would take time to first switch from the police box position to the main channel position, and then select the channel that is broadcasting baseball from the main channel selection button, which would cause important There is a risk of missing the scene. Also, if the program you are watching is not interesting, you can use the clock pulse generator circuit.
By turning on the pulse generation circuit, all main channels can be automatically tuned in sequence at appropriate intervals, making it easy to find out what other programs are being broadcast. seconds or 1
If you set it to minutes, you can also know what other stations are doing during commercials. Furthermore, since the automatic switching can obtain a pulse from the connected circuit, it can be applied to the audio circuit via the audio muting circuit to eliminate unpleasant switching noises.

In the above embodiment, the main channel is a multi-station preset system, and the sub channel is a single-station continuously variable tuning system, but of course there is no need to limit it to this, and any tuning system using an electronic tuner can be used. Furthermore, switching not only between two stations but also multiple stations above three stations can be performed by changing the mode selection circuit, selection switch circuit, and band switch circuit. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional preset electronic tuning type tuning device, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a detailed circuit diagram of FIG. MCG...Main channel selection circuit, SCS...Sub channel selection circuit, MDS...Mode selection circuit (a circuit that automatically switches and connects multiple channel selection circuits to the electronic tuner), SSW...Selection switch Circuit, BSW...Band switch circuit, MU...
Audio muting circuit, 10...electronic tuner, 14...mode switch (switch means for connecting and maintaining one of the tuning circuits to the electronic tuner),
40... Muting pulse output terminal.

Claims (1)

[Claims] 1. A single electronic tuner, a plurality of tuning circuits,
A circuit for automatically switching and connecting these tuning circuits to the electronic tuner, and a switch means for connecting and maintaining one tuning circuit among the plurality of tuning circuits to the electronic tuner. A channel selection device comprising means for extracting input pulses from the automatic switching connection circuit to the audio muting circuit.