JPS5843297Y2 - Denshisenkiyokusouchi - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electronic channel selection device that can be operated by remote control.

In a so-called electronic tuning device that uses a variable capacitance diode as a tuning element, a flip-flop circuit is installed, and the emitter of each transistor constituting each flip-flop circuit is grounded via a common resistor. The configuration is such that only one of the selected 7 lip-flop circuits is inverted, and the output of the corresponding variable voltage divider is applied to the variable capacitance diode to select the desired channel. Furthermore, in order to meet the need for sequential channel selection for purposes such as remote tuning, a ring counter circuit is configured by each of the flip-flop circuits, and a desired channel is selected by sequentially shifting the ring counter circuit using a remote control signal. Configure to select channels sequentially.

When such a sequential channel selection method is adopted, if the number of receivable stations is small, empty channels (unused channels) are sequentially selected, resulting in various inconveniences as described later.

The present invention proposes an electronic channel selection device configured to automatically skip over empty channels in such a sequential channel selection method.

First, the operation of this type of electronic channel selection device will be explained with reference to the schematic circuit diagram shown in FIG.

For convenience of explanation, it is assumed that the electronic channel selection device shown in FIG. 1 is selected from among five layers.

In Figure 1, numbers 1albtlc and 1dtle are the 1st, 2nd, 3rd, 4th, and 5th channel selection buttons that detect finger contact and generate output, and 2a, 2b, 2c, 2d, and 2e are corresponding buttons. 1st, 2nd, and 3rd buttons whose states are inverted based on the detection output of the selected channel selection button.
, fourth, and fifth flip frogs, and the shift pulses constitute a ring counter as a whole.

3a, 3b, 3c, 3d. 3e is a first, second, third, fourth, and fifth selection switch for grounding the other end of a corresponding potentiometer, which will be described later, based on the corresponding flip-flop output; 4a, 4b, 4c, 4d, and 4e are Display switches 5ay5b and 5c5e apply voltages to light emitting diodes (to be described later) based on the corresponding flip-flop outputs; potentiometers 6a t 6b apply tuning voltages to VHF electronic tuners and UHF electronic tuners to be described later;
t 6c t 6d t 6e are first, second, third, fourth, and fifth reverse current blocking diodes 7a and 7b that block reverse current generated at the output terminal of each potentiometer.
, γc, 7d, and 7e are the first
, the second, third, fourth and fifth light emitting diodes, 8 and 9 are:
The VH applies the output of each potentiometer to a varicap diode and tunes the station based on each voltage.
F"electronic tuner and UHF" electronic tuner, R1 is a high resistance for making the backflow blocking diode of the output terminal of the potentiometer conductive and blocking the other backflow blocking diodes, and the high resistance is It is inserted between a power supply VT connected to the other end of each potentiometer and a tuning voltage supply path 14 leading to a variable capacitance diode of the tuner.

The operation of this device will be described below.

Each potentiometer is adjusted in advance so as to apply a voltage that enables tuning to the variable capacitance diodes of the VHF electronic tuner 8 and the UHF electronic tuner 90.

Note that the first to fifth potentiometers 5a, sb, 5
c.

For convenience of explanation, the channels selected by the applied voltages 5d and 5e will be referred to as a first station, a second station, a third station, a fourth station, and a fifth station.

First, when the power supply voltage is applied, the ring counter 2
Only the specific 7 lip-flop is turned on.

Therefore, in the case of this device, the first station associated with the first flip-flop 2a is selected.

Next, when selecting a channel, for example, when a finger touches the third channel selection button 1c, the first flip-flop 2a becomes OFF" and the third flip-flop 2c becomes ON.

Therefore, the third selection switch 3c is closed by the 37th lip-flop output, and the other end of the third potentiometer 5c is grounded.

The third potentiometer 5c, now energized, generates a voltage for third station selection at its output terminal, and selects one channel in VHF or UHF.

On the other hand, the third flip-flop output closes the third display switch 4c and causes the third light emitting diode 7c to emit light, thereby indicating the selected station position.

Furthermore, if you want to perform channel selection operations using a remote device such as a remote control,
The receiving microphone 11 receives the ultrasonic waves generated from the remote control 10, and outputs the microphone output to a shift pulse generating circuit.
The output of the shift pulse generating circuit is connected to the ring counter 2 so that it can be inputted thereto.

Therefore, since the output of the remote control 10 shifts the ring counter 2, for example, if the remote control output is received while the second station is being selected, the third station is selected.

However, since the shift Hals generating circuit 12 shifts the ring counter 2 only in one direction, the remote control output must be generated four times in order to select the second station during the third station selection.

However, in order to use an electronic channel selection device as a product in a television receiver, at least 8 stations are required, and in reality, it is possible to select about 133 stations in order to provide versatility.

Therefore, even if there are many vacant channels depending on the region, the remote control output must be generated 12 times when selecting a channel.

The present invention proposes an electronic channel selection device that is devised to automatically skip over unnecessary empty channels when sequentially selecting channels using shift pulses.

The present invention will be described below with reference to an illustrative embodiment.

This embodiment is an addition of the present invention to the conventional example shown in FIG. 1, and the same elements are denoted by the same reference numbers, redundant explanations are omitted, and only the parts related to the present invention will be explained.

First, from the voltage applied to the variable capacitance diodes of the VHF-UHF dual-type tuners 8 and 9, a Zener diode Z is used as a means for detecting a voltage that cannot be tuned.
Provide D.

That is, the Zener diode ZD becomes conductive when the variable capacitance diode leaves the tuning range, and inputs a conductive current to the preset pulse generation circuit.

In the preset pulse generation circuit 13, Trl is a first transistor whose base is connected to the Zener diode ZD and becomes conductive only when the Zener diode ZD is conductive, and Tr2 has an emitter in common with the first transistor T r 1 . The collector output of the first transistor Tr1 is used as a base input, and the second transistors C1 and R2, which are non-conductive only when the first transistor Trl is conductive, are connected to the collector output of the second transistor Tr2 to form a differentiating circuit. A capacitor and a second resistor are shown respectively.

The differentiating circuit therefore generates a positive pulse at the moment the second transistor becomes non-conducting.

Below, we will discuss the skipping station selection during use.

For convenience of explanation, an example will be explained in which there are three receivable stations.

First, when setting the voltage of the potentiometers before use, be sure to set them in the order in which they are shifted from the potentiometers corresponding to the flip-flops that are turned on when the power is turned on.

The potentiometer that remains after the setting is set to the maximum setting voltage to remove it from the tunable range of the varicap diode of the VHF-UHF' electronic tuner.

Therefore, in the case of this embodiment, the voltage setting digit of the potentiometer is not set in the order of the first station, the second station, and the third station, and the setting value of the potentiometer is set to the maximum value in the fourth station and the fifth station.

Therefore, if a remote control output is generated while receiving the third station, the fourth
The flip-flop 2d is turned on and a tuning voltage is applied to the fourth potentiometer, but since the voltage value of the potentiometer reaches the maximum, the VHF-UHF electronic tuners 8 and 9 cannot perform tuning operation, and the zener Only the diode ZD becomes conductive and outputs to the preset pulse generation circuit 13 manually.

Therefore, the preset pulse is input to the ring counter 2, and the ring counter is in the same state as when the power is turned on, that is, only the first flip-flop 2a is in the ON state.

Therefore, this device selects the first station after the third station, skipping over the unused fourth and fifth stations.

Therefore, according to the present invention, even if the number of stations of the channel selection device is greater than the number of receivable stations, the efficiency is extremely low because no empty channel is selected when a remote control output is generated.

In addition, in this invention, the transition from an empty channel is turned on when the power is turned on, and 7 lip of the predetermined channel is selected as 70, so the necessary channels are set sequentially from the flip-flop of the predetermined channel that serves as the reference (this is done using a potentiometer). , subsequent channels can be determined as unnecessary channels (empty channels), and therefore, the potentiometer output of the first unnecessary channel returns the on state to the predetermined channel, so the effect is that it is possible to form the minimum necessary loop as a ring counter. There is.

Another advantage is that the connection structure of the circuit for realizing the interleaving becomes simple.

Moreover, in such a case, you only need to set the potentiometer of the first unnecessary channel so that it is outside the tuning voltage range, and there is no need to adjust the settings of the potentiometers of the subsequent unnecessary channels. You can also expect advantages.

Note that when the power is turned on, the output pulse of the circuit 13 is turned on, and the output pulse of the shift pulse generating circuit 12 is not added to the flip-flop.
It is conceivable to skip over empty channels by adding VT, but in this case, the shift is caused by the pulse generated from the circuit 13 when the power is turned on [Trl is turned on due to the application of VT, and a pulse is generated when Tr2 is turned off]. Since there is a possibility that the pulse generation circuit 12 is activated and the receiving channel is uncertain when the power is turned on, in the present invention, as described above, the pulse generated in the circuit 13 is turned on when the power is turned on or added to the flip-flop of a predetermined channel. ing.

By doing this, the present invention not only ensures that the channel settings are made when the power is turned on, but also has the advantage that there is no need for a separate means to turn on the flip-flop corresponding to a predetermined channel when the power is turned on. can.

The reason why a pulse is generated in the preset pulse generation circuit 13 when the power is turned on is as follows.

First, the Zener diode ZD has a movable terminal that is turned on by a voltage higher than the voltage of the potentiometer which is shifted to the power supply VT side and is outside the tuning voltage range.

However, when both flip-flops are off, the power supply VT
When the power is turned on when is applied through the resistor R1, the Zener diode ZD becomes conductive and the first transistor Trl is also turned on.

Therefore, the second transistor Tr2 is turned off and the power supply vB
A current flows from the resistor R3 to the capacitor C1 to the second resistor R2, and a positive voltage is generated at the connection point between C1 and R2.

This positive voltage decreases as C1 charges, and becomes O when charging of C1 is completed.

In this way, a pulse voltage is generated at the connection point between C1 and R2 when the power is turned on.

[Brief explanation of the drawing]

FIG. 1 shows a circuit diagram of a conventional electronic channel selection device, and FIG. 2 shows a circuit diagram showing an embodiment of the present invention. Explanation of main drawing numbers, 2...Ring counter, 5ay5b
, 5c, 5a, 5e--first, second, third, fourth, fifth, potentiometer, 8...VF (F
Electronic tuner, 9...UHF electronic tuner, ZD...
- Zener diode, 13... preset pulse generation circuit.

Claims (1)

[Scope of utility model registration request] One end of a potentiometer is connected to the output side of each flip-flop constituting a ring counter whose ON state is sequentially incremented by a shift pulse so that the flip-flop is activated when the flip-flop is ON, and the other end of this potentiometer is connected to A tuning voltage supply path to the tuner is connected to the power supply through a resistor, and the output voltage of the potentiometer is connected to the tuning voltage supply path through a backflow blocking diode connected to the movable end of the potentiometer and the tuning voltage supply path. In the electronic channel selection device, the movable end of the potentiometer of the empty channel is shifted to the power supply side and set in advance to output a voltage outside the tuning voltage range. A detection means that operates at a voltage higher than the voltage when the potentiometer of the empty channel is activated is connected to the tuning voltage supply path, and a circuit is provided that generates a pulse based on the output of the detection means, and the pulse is generated. An output pulse of the circuit is supplied to a flip-flop of a predetermined channel of the ring counter so that the flip-flop of the predetermined channel is turned on, so that the receiving state is transferred from the empty channel to the predetermined channel. Electronic channel selection device.