JPS5936471B2 - television receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit that displays a deviation in an adjustment location of a television receiver.

A typical television receiver has brightness, contrast,
An adjustment circuit that allows adjustment of image quality, volume, sound quality, color saturation, hue adjustment, etc. according to so-called viewer preferences,
On the contrary, there are two types of adjustment circuits, such as local, horizontal synchronization, and vertical synchronization, that are originally unnecessary for viewers and are installed by manufacturers to respond to environmental changes such as aging of receivers. There are adjustments to be made.

Moreover, the local, horizontal synchronization, and vertical synchronization adjustment knobs, which are unnecessary for viewers, are placed in locations where viewers can easily touch them, such as on the side of the receiver, for ease of service. For example, when a child accidentally touches such an adjustment part, or an adult touches it by mistake, there are generally few people who can adjust it to the normal state because they are not accustomed to adjusting it, so they have to call an electrician at an electronics store. The current situation is that I have to call. Further, although it is possible to store such adjustment points inside the receiver, if they actually become misaligned due to aging, etc., the back plate must be opened each time, which impairs serviceability. Furthermore, opening the back plate and making adjustments by the general public may lead to more mistakes in preparation, and furthermore, it is extremely dangerous from a safety standpoint. Also, local, horizontal synchronization, such as
Even people who are quite accustomed to adjusting vertical synchronization may not be able to make a perfect adjustment when it comes to determining the symptoms of synchronization being disrupted due to local misalignment, or conversely, the symptoms of synchronization being disrupted and local misalignment. It becomes extremely difficult. Therefore, we have developed a display device that eliminates these drawbacks of the conventional technology and allows even the general public to see at a glance which adjustment point is out of alignment when the adjustment points that do not depend on the viewer's preference, such as local, horizontal, or vertical synchronization, are out of alignment. devised.

First, this display device will be explained. In Figure 1,
1 is an antenna, 2 is a tuner, 3 is a local adjustment knob for adjusting the local oscillation frequency (local frequency) of the tuner to obtain a regular intermediate frequency, 4 is an intermediate frequency amplification circuit, 5 is a video detection circuit, 6 is a video amplifier, T is a cathode ray tube, 8 is a synchronization signal separation circuit, 9 is an integration circuit for obtaining a vertical synchronization signal, 10 is a vertical oscillation circuit, 11 is a vertical signal amplification circuit (vertical sawtooth wave amplification circuit, 12 is a vertical output circuit, 13 is a vertical synchronization volume that adjusts the oscillation frequency of the vertical oscillator, 18 is a differentiation circuit for obtaining a horizontal synchronization signal, 19 is a horizontal phase detection circuit, 20 is a horizontal oscillation circuit, and 21 is a horizontal Output drive circuit, 22 is a horizontal output circuit,
23 is a horizontal oscillation frequency adjustment volume.

Since the circuits with the above functions are the basic circuits of a general television receiver, a description of their operation will be omitted. 14, 15, 16, IT
14 is an indicator circuit for adjusting the vertical synchronization knob when the vertical oscillation frequency is shifted and synchronization is flowing on the screen. First, 14 detects whether the vertical oscillation frequency matches the vertical synchronization signal. The outputs of the integrating circuit 9 and the vertical oscillation circuit 10 are added as inputs.

The output of the gate circuit 14 is converted to D by 15 smoothing circuits 15.
It is converted into a DC voltage, and appears as a DC voltage depending on whether the outputs of the integrating circuit 9 and the vertical oscillation circuit 10 are in phase or out of phase. 16 is a switching circuit, which is turned on or off depending on the output of the smoothing circuit 16; the switching circuit 16 controls a display circuit IT; this display circuit is provided near the vertical synchronization volume 13; When the integrator circuit 9 and the vertical oscillation circuit 10 are in phase, the display circuit IT is prevented from operating by the switching circuit 16.

When the phases are different, the display circuit IT is set to operate in reverse. In this way, if the vertical synchronization is disturbed for some reason, even a general viewer can understand at a glance by the operation of the display circuit IT that all he has to do is adjust the vertical synchronization knob. 24, 25, and 26 are display circuits when the horizontal synchronization is disturbed, and these are also the outputs of the differentiating circuit 8 and the horizontal output circuit 2.
The phase of the horizontal synchronizing signal and the horizontal oscillation pulse is detected by the phase detection circuit 24 from the output of the horizontal synchronizing signal and the horizontal oscillation pulse, and the output is smoothed by the smoothing circuit 25, and added to the switching circuit 26. This is an attempt to make it work.

28, 29, 30, and 31 are display circuits when the local frequency is shifted; 28 is a single-tuned carrier amplifier tuned to the intermediate frequency; its output changes depending on the state of tuning, that is, the state of local shift.

29 is a smoothing circuit, 30 is a switching circuit, and 31 is a display circuit installed near 3, which automatically operates when the local position shifts.

FIG. 2 shows the parts 10 and 14 to 16 in FIG. 1 in a concrete circuit.

FIG. 3 shows voltage waveforms at various parts for explaining FIG. 2. In FIG. 2, numerals 32 to 38 indicate the vertical oscillator portion of FIG. 10. Since the operation of the oscillator is well known, it will be omitted, but the capacitor 32 is connected to the base of the 3T as shown in Figure 3a.
When the vertical synchronizing signal shown in FIG. 3 is applied, the oscillation output becomes a sawtooth wave as shown in FIG. This output waveform passes through an emitter follower circuit of a transistor 44 and a resistor 45, and its output is divided by resistors 46 and 41 and applied to the base of a transistor 48. A vertical synchronizing signal is applied to the base of transistor 49 through capacitor 39 and transistor 42 . The transistors 48 and 49 constitute a gate circuit, and the transistor 48 is turned on at the 11th level or higher of the waveform shown in FIG. flows and turns on transistor 51. Therefore, the collector of the transistor 51 receives the voltage shown in FIG. 3c only when both signals are in phase.
A pulse appears.

This waveform is converted into the smooth waveform shown in FIG. 3d by an RC integrating circuit including a resistor 52 and a capacitor 50. This is passed through an emitter follower circuit of a transistor 43 and a resistor 41,
It is added to the base of the switching transistor 40. Therefore, at this time, the transistor 40 is turned on and no voltage is applied across the lamp IT, so the lamp does not light up. When the vertical synchronization signal and the oscillation output are out of phase, the gates of transistors 48 and 49 are not turned on, so transistor 51 is turned off, and therefore transistor 40 is also turned off, and +B voltage is applied to lamp IT through the resistor, turning lamp IT on. do. Figure 4 is similar to Figure 1 19, 20 and 24.
A specific circuit of the ~2T portion is shown. FIG. 5 shows waveforms of various parts of FIG. 4. FIG. 5a shows a horizontal synchronizing signal, and FIG. 5b shows a horizontal flyback pulse generated by a horizontal flyback transformer, which are applied to the bases of transistors 54 and 53, respectively. Since this portion of the circuit is the same as that in FIG. 2, its explanation will be omitted. When the horizontal synchronizing signal (a) in FIG. 5 and the horizontal flyback signal (b) in FIG. 5 are in phase, the lamp 2T is off, and when they are out of phase, the lamp 2T is turned on. Figure 6 is Figure 1 28-3
1 concrete circuit, 55 is the video intermediate frequency (58.7
This amplifier circuit has a tuning circuit tuned to 5MHz). The output of this amplifier circuit is connected to a diode 56 and a capacitor 5.
When smoothed by T, the output of the emitter follower circuit consisting of the transistor 58 and the resistor 59 obtains a DC voltage that changes as shown in Figure T (a) with respect to the shift in the video intermediate frequency. If the setting is made so that the transistor 60 is turned on when this DC voltage is equal to or higher than level 14 in Figure T, then 1
When the level of 14 reaches the corresponding frequency deviation F, the lamp 31 lights up. The above is an explanation of the operation of the specific circuit.
As you can see from these operations, in the case of the circuit described above, if the adjustment part shifts during normal use, it will operate normally and be convenient for the viewer, but when switching channels This will cause inconvenience. For example, at the moment the channel is switched, there is no synchronization signal, and the local frequency is also free-running oscillation. Therefore, in such a case, the same symptoms as synchronization deviation or local deviation may occur, causing the display circuit to operate and causing the viewer to become anxious every time he or she switches channels. Therefore, the present invention aims to eliminate such drawbacks and provide a circuit in which the display circuit does not operate when switching channels.
An embodiment of the present invention will be described below with reference to the drawings.

FIG. 8 shows a specific circuit of the main part of the receiver of the present invention.
In FIG. 8, 61 is a high frequency generation source. Although a separate oscillator may be provided, in the case of a color television receiver, the output of a 3.58 MHz chroma oscillator can be used. The output terminal of this high frequency generation source 61 is connected to a channel knob 64 through capacitors 62 and 63. As shown in FIG. 9, the channel knob 64 and the capacitor 63 are connected by a contact piece 66 so as not to hinder the rotation of the knob 64.
5 and is electrically connected to the capacitor 63 through the capacitor 63. The intersection of capacitors 62 and 63 is connected to a detector 67 through a capacitor 66. Now, when a person touches the knob 64, a high frequency signal flows due to the ground capacitance of the human body. The capacitor 62 is selected to be sufficiently small compared to the human body capacity.
Generally, the capacitance of the human body to ground is about 50PF, so the capacitor 62 may be selected to be within 5PF.
Then, when the channel knob 64 is touched, the amplitude of the high frequency signal at the intersection of the capacitors 62 and 63 becomes smaller. A detector 67 converts the amplitude change into a DC voltage. knob 6
4, the detection output voltage decreases, turning off the transistor 68. Then, transistors 69, 70,
Each base voltage of 71 is applied through a resistor 72 so that it is turned on. The collectors of the transistors 69, 70, 71 are located at the intersections 16, 17, 26, 27, 30,
31 intersections, 17, 27,
Since no voltage is applied to each of the display circuits 31, they do not operate.
When the channel knob is not touched, a signal with a large high frequency amplitude is applied to the detector 67, so the transistor 68 is turned on, the transistors 69, 70, and 71 are turned off, and the display circuit operates as before. . As described above, according to the present invention, the display circuit does not operate when switching channels, so the viewer does not get confused when switching channels and does not have to worry about unnecessary things. Of course, when a local frequency shift or a vertical or horizontal synchronization shift occurs, the display circuit can display what has shifted.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a television receiver conceived prior to the present invention, Fig. 2 is a circuit diagram of a part of the same receiver, and Fig. 3 A, b, c, d, e, f are Figure 4 is a circuit diagram of other parts of the receiver; Figures 5A, b, c, d, e, f are waveform diagrams for explaining the circuit;
Figure 6 is a circuit diagram of other parts of the same receiver, Figure 7A
, b are waveform diagrams for explaining the circuit, FIG. 8 is a circuit diagram of other parts of the receiver, and FIG. 9 is a perspective view of a device constituting the circuit of FIG. 9...Integrator circuit, 10...Vertical oscillation circuit, 14...Gate circuit, 15, 25, 29.
... Smoothing circuit, 16, 26, 30 ... Switching circuit, 17, 27, 31 ... Display circuit, 18 ... Differentiation circuit, 19 ... ... Horizontal phase detection circuit, 24 ... Phase detection circuit, 64.
... Channel knob, 61 ... High frequency source, 67 ... Detector, 68, 69, 70,
71...transistor.

Claims (1)

[Claims] 1. A detection circuit is provided to detect deviations in adjustment points that do not depend on the viewer's preferences, such as local frequency, horizontal synchronization, vertical synchronization, etc., and a display circuit is provided to display the output of this detection circuit, so that tuning operations can be performed. A television receiver comprising a circuit that sometimes controls the display circuit to be in an OFF state regardless of the output of the detection circuit.