JPS5857023B2 - How to display presets on a television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a preset display method for displaying a preset voltage of a television receiver having a voltage responsive capacitive element as a tuning element and facilitating preset adjustment of the television receiver.

The conventional preset display method shown in FIG. 1 is based on an index means 3 that moves in the axial direction of a preset adjustment volume 1 having a preset adjustment knob 1a shown at the opening of the figure, and is engraved on a transparent part of its case. The preset status is displayed by the characters provided.Generally, eight or more such volumes 1 are arranged in front of the television receiver 4, so the display section of each volume is The disadvantage is that it is small and difficult to see.

There is also a method of distributing the voltage applied to the voltage-responsive variable capacitance element on the front surface of the cabinet 4a of the receiver 4 using a voltage make 5, as shown in the conventional preset display shown in FIG. The disadvantage is that it is difficult to see and expensive.

The conventional method shown in FIG. 3 projects the voltage applied to the variable capacitance element as stripes 6 or dots on the cathode ray tube screen 4b, which has the advantage of being easier to see than in FIGS. 1 and 2. , characters such as channel number VH, 2, 12
Since this is also projected on the cathode ray tube screen 4b, it is inevitable that the display signal and its circuit configuration will become complicated.

The present invention proposes a new and effective preset display method that takes advantage of the advantages of preset display using a cathode ray tube screen and avoids the disadvantages of the method shown in FIG.

That is, the method of the present invention projects a line on the cathode ray tube screen that changes over approximately the entire screen in accordance with the voltage applied to the variable capacitance element, and also projects a line that is close to the cathode ray tube screen so that it can be seen from the outside during preset adjustment. A scale such as a scale is provided inside the door housing the preset adjustment knob, etc., and the position of the line projected on the cathode ray tube screen is measured using the scale to determine the value of the preset voltage. .

Examples of this method will be described below with reference to the drawings.

In FIG. 4, Ql is a switching transistor, and a vertical synchronizing signal P is applied to its base.

The switching transistor Q1, resistor R1, and capacitor C1 constitute a sawtooth wave generating circuit 7, which is shown in FIG.
A sawtooth wave voltage S1 shown in 1) is generated.

That is, while the transistor Q1 is off, the capacitor C1 is charged by the power supply 8 through the resistor R1, and the voltage across the capacitor C1 gradually increases.

When the vertical synchronizing signal P arrives at the base of the transistor Q1, the charge of the capacitor C1 is instantaneously discharged during this signal period between the collector and emitter of the transistor Q1, so the voltage across the capacitor C1 becomes zero during the period. In the next vertical scanning period, the potential becomes a sawtooth wave that rises again from zero potential.

The output voltage of the sawtooth voltage generation circuit 7 is applied to the base of a differential pair transistor Q2 constituting a differential amplifier 8 at the next stage.

The presetting applied voltage applied to the variable capacitance element of the tuner is branched and applied from the terminal 10 to the other differential pair transistor Q3.

Now, the level of this applied voltage is E in Fig. 5 (11).
x, the output terminal 9 of the differential amplifier 8 is
As shown in 1), a pulse with a width corresponding to a sawtooth voltage exceeding level EX is generated.

Since the width of this pulse depends on the level EX, the degree of tuning appears as the width of the pulse.

If the pulses are supplied to the video signal circuit from the output terminal 9, a raster of black and white B can be obtained on the screen 4b of the cathode ray tube, as shown in FIG.

The boundary line 11 changes over almost the entire screen by changing the preset applied voltage EX.

This line 11 is connected to the screen 4b in the cabinet 4a.
It is compared with a scale 12 such as channel letters and scales provided inside a door housing a preset adjustment knob and the like so that it can be seen from the outside during preset adjustment in close proximity to the door.

The projection of the line 11 on the cathode ray tube screen 4b should be done only during presetting, so use an appropriate switch to supply operating power to the circuit shown in Figure 4 only during presetting, or connect the power to the output terminal without leaving the power on. 9 is transmitted to the subsequent circuit.

It goes without saying that if the output of the differential amplifier 8 is applied to the color signal circuit instead of the video signal circuit, the screen will not be black and white but will have two chromatic colors.

In addition, in Figure 4, if the signal applied as the drive signal for the switching transistor Q1 is a horizontal synchronization signal instead of a vertical synchronization signal, the border line on the screen will appear vertically, so in this case, the preset adjustment knob It goes without saying that a door for storing such items should be provided above or below the screen.

As described above, in the present invention, a line is displayed on the cathode ray tube screen that changes over the entire screen according to the voltage applied to the tuning variable capacitance element, and the scale is determined by the inside of the door that houses the preset adjustment knob etc. near the screen. Since a large preset display is realized, it is easy to see and the configuration of the preset display device is extremely simple.

In addition, there is no need for a space to provide a scale on a part of the front surface of the television receiver, and since the door is closed except during preset adjustment, the scale is not visible from the outside of the television receiver, which is preferable in terms of design.

As described above, the present invention is effective and extremely effective for preset display on television receivers.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are all front views showing the front side of a television receiver for explaining a conventional preset display method of the television receiver. 4 to 6 show a device implementing the preset display method for a television receiver according to the present invention. FIG. 4 is a circuit diagram of the device, FIG. 5 is a signal waveform diagram, and FIG. FIG. 3 is a front view of the receiver. EX... Applied voltage, P... Vertical synchronizing signal, 4b... Braun tube screen, 7...
Sawtooth wave generation circuit・8...Differential amplifier, 11・
... Line, 12 ... Scale.

Claims (1)

[Scope of Claims] 1. A method for displaying a preset voltage of a television receiver having a voltage-responsive variable capacitance element as a tuning element, the method of displaying a preset voltage on a cathode ray tube screen in accordance with the voltage applied to the variable capacitance element. In addition to displaying the changing line, a scale such as a scale is provided inside the door that houses the preset adjustment knob etc. so that it can be seen from the outside when adjusting the preset, and is located close to the cathode ray tube screen, and the position of the line is measured using the scale. A preset display method for a television receiver, characterized in that: 2. In order to project a line that changes over approximately the entire screen in accordance with the applied voltage of the variable capacitance element, apply the applied voltage to one control electrode of the differential pair of the differential amplifier, and A voltage of a sawtooth wave electrostriction generation circuit controlled by a vertical synchronization signal or a horizontal synchronization signal is applied to the other control electrode, and the comparison output of the differential amplifier is supplied to a video signal circuit or a color signal circuit. A preset display method for a television receiver according to claim 1, characterized in that: