JPS61295715A - Frequency presetting device - Google Patents

Abstract

PURPOSE:To constitute a frequency presetting device at low cost and reduce its secular change, and to vary a tuning speed continuously by leading a desired tuning voltage out by the charging and discharging of an integration circuit through the selection of the 1st of the 2nd switch circuit and supplying it to a voltage control channel selecting circuit. CONSTITUTION:When the switch part 61 of the 1st switch circuit 6 is pressed, the integration circuit 9 consists of a resistance part 62 and a capacitor 8 and a charging speed is set freely by varying pressing force and increasing and decreasing a resistance value. When the output voltage of this integration circuit 9, i.e. tuning voltage reaches a desired value, is held at it is by opening the switch part 61 and the tuning voltage is digitized by the voltage control channel selecting circuit 2 through the operation of an external switch 5 and stored in a memory circuit 3. When the tuning voltage is lowered, the switch part 71 of the 2nd switch circuit 7 is pressed and the integration circuit 9 is composed of a resistance part 72 and capacitor 8 and discharge to an earth terminal.

Description

[Detailed Description of the Invention] [Field of Application] This invention relates to a frequency presetting device in a television receiver, and particularly to simplifying the presetting operation thereof [Prior Art] Fig. 2 shows, for example, Machine color TV CT-2228
In Figure 2, there is a circuit diagram showing the frequency presetting device of the C-produced rice that has already been made into a Kfi product with F'M. (1) is the frequency presetting circuit consisting of the DC voltage supply terminal ■ and the multi-rotation variable resistor VR. Then output the desired tuning voltage from the variable resistor VR. (2) A, 6 voltage control channel selection circuit which receives this tuning voltage and is constituted by, for example, a multiplication circuit.

(3) is a memory circuit that stores the output of this voltage control channel selection circuit, (41 is a tuner that selects the memory channel of this memory circuit, 151 is the above voltage control, l!!1 station circuit (2)
It is an external type control unit.

The operation shown in FIG. 2 will be explained. The frequency preset circuit (1) is composed of the multi-rotation variable resistor VR as described above. When presetting the n2 frequency, K rotates the variable resistor VR to derive a desired tuning voltage. To this tuning voltage, voltage control channel selection circuit +21
The K input is converted into a digital value, and this digital value is stored in the memory circuit (3) by operating an external type input (5).

Then, the value stored in this memory circuit (3) is selected by the tuner (4).

[Problem that the invention seeks to solve]

Since the conventional frequency presetting device uses the multi-rotation variable resistor VR as described above, delicate operation of the variable resistor is difficult.

The selection speed is slow, so Zhou Heya? :nThere was a problem that it took time to set the preset accurately.

The present invention has been made to solve these problems, and it is an object of the present invention to provide a frequency presetting device that is easy to operate and shortens the time required to preset the frequency, while making the variable resistor for single frequency presetting unreliable. With the goal.

[Means for solving problems]

The frequency presetting device according to the present invention includes first and second switch circuits whose resistance value changes depending on the pressing force, one end of the first switch circuit being a DC voltage supply terminal, and one end of the second switch circuit being a DC voltage supply terminal. One end was connected to the ground terminal, and the other end of the valley switch circuit was connected to a common capacitor to form an integrating circuit, and the tuning voltage was derived from the output terminal of this integrating circuit.

[Effect]

In this invention, by selecting the first switch circuit, the integrating circuit is charged, and by selecting the second switch circuit, the integrating circuit is discharged. Moreover, since each switch circuit has a resistance value that changes according to the pressing force, the photoelectric or discharge time of the integrating circuit can be adjusted at will, and therefore the time to obtain the desired tuning voltage can be freely changed. Can be done.

[Embodiments of the invention]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.
) to (5) are the same as or equivalent to the above conventional device,
(6) is a first switch circuit whose one end is connected to the DC voltage supply terminal VK, and includes a switch part (61) and a resistor part (62) whose resistance value changes depending on the pressing force of this switch part.
It is composed of V. (7) is a V5 switch part (71) which is a second switch circuit whose one end is connected to the ground terminal.
) and a resistance part (72) whose resistance value changes depending on the pressing force of this switch part. (8) is connected to each of the above switch circuits (6+, (71) with a common capacitor connected to the other end of the above resistor section (62) or (7).
2) Toyo! 1llll batch circuit).

In Fig. 1, when the switch circuit (61) of Mouse 1 is pressed, the M branch circuit (9) is configured as V by the resistor (62) and the capacitor (8), and the DC voltage is The charging speed can be freely set by changing the pressing force of the switch part (61) and adjusting the resistance value of the resistor part (62) 5. When the output voltage or tuning voltage reaches a desired value, if the switch section (61) is opened, the voltage is maintained as it is, and the voltage control tuning circuit (2 ) converts the tuning voltage digitally, and sends this digital value to the memory circuit (3
). To lower the tuning voltage, use the second
By pressing the switch part (71)'& valve of the switch circuit (7), the circuit (9) for ljt is constructed of a resistor part (72) and a capacitor (8), and is performed by discharging to the ground terminal. . The discharge rate at this time is the switch part (71)
The resistance value of the resistance part (72) can be freely set by changing the pressing force of the resistance part (72).

In addition to supplying a constant @ current voltage to the DC voltage supply terminal (2), the same operation can be performed by supplying a pulsating voltage containing a DC component.

〔Effect of the invention〕

As described above, according to the present invention, a desired tuning voltage can be obtained by charging and discharging an integral circuit by operating a switch, and the speed can be adjusted by changing the pressing force of the switch, so that the device can be manufactured at low cost. In addition to being able to be configured to reduce aging, preset operations are easy and tuning speeds can be changed steplessly.

It is possible to obtain the effect that the preset time can be shortened.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, and Fig. 2 is a circuit diagram showing a conventional frequency presetting device. In Fig. 1, (1) is a frequency precent circuit, and (6) is a switch section (61). The first switch circuit 5 (7) consists of a switch section (71) and a resistance section (72), and a second switch circuit consists of a switch section (71) and a resistance section (72), a t81U capacitor. (9) &Y branch circuit, (2) is a current voltage supply terminal, (2) is a voltage control channel selection circuit, and (3) is a memory circuit. Note that the same reference numerals in the valley diagram indicate the same or corresponding parts.

Claims (1)

[Claims] In a frequency presetting device that stores a desired tuning voltage in a memory circuit via a voltage control tuning circuit, it consists of a switch part and a resistor part, and the resistance value of the resistor part changes according to the pressing force of the switch part. The first and second terminals are connected to the DC voltage supply terminal and the ground terminal.
and a common capacitor connected to the other ends of the first and second switch circuits and forming an integrating circuit with each resistor section, A frequency presetting device characterized in that a desired tuning voltage is derived from the integrating circuit by charging and discharging the integrating circuit by selecting a switch circuit, and supplies this to the voltage-controlled tuning circuit.