JPS6378608A - Channel selection device - Google Patents

Abstract

PURPOSE:To inform a reception state to a user, and to prevent the irregularity of a picture from occurring at time of no signal, by supplying a video signal to a CRT by controlling a signal selection circuit for a channel with a signal, and supplying a fixed signal from a signal generation circuit to the CRT for the channel without the signal, at the time of operating a memory. CONSTITUTION:A switching signal '1' is supplied from a channel selection circuit 9 to a terminal 22 at a preset time. Meanwhile, the signal '1' is supplied from a signal detection circuit 8 to a terminal 21 when the signal is present, and it is inverted at an inverter 24, and is changed to a signal '0', then it is added on an AND circuit 25. The signal selection circuit 5 introduces the output of an amplifier circuit 4 to the CRT6 (display device) 6, and displays an image by a broadcasting signal. However, in the channel without the signal, the signal '0' is supplied from the signal detection circuit 8 to the terminal 21, and it is inverted at the inverter 24. In this way, the signal selection circuit 5 is switched so as to introduce the fixed signal from the signal generation circuit 7 to the CRT6, and the image by the fixed signal is displayed on the CRT6, and the irregularity of the picture due to noise, etc., can be prevented from occurring.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a television receiver.

When receiving the broadcast of a predetermined channel, the data of each channel is stored (preset) in the memory in advance, and by key operation, the stored arbitrary channel data is read out and the desired channel is selected. Regarding equipment.

(Prior art) Fig. 3 is a block diagram showing a conventional channel selection device, in which 1 is an antenna, 2 is a tuner, 3 is a signal processing circuit that performs intermediate frequency amplification and video detection, and 4 is a video amplification circuit. .

The output of this amplifier circuit 4 is passed through a signal selection circuit 5 to CR,
The signal selection circuit 5 is also supplied with a signal from a fixed signal generation circuit 7. Furthermore, the output of the signal processing circuit 3 is supplied to the signal detection circuit 8,
The detection output is supplied to the tuning circuit 9. A memory 10 and a key input circuit 11 are connected to the channel selection circuit 9.
The tuning circuit 9 is also connected to the tuner 2 and the signal selection circuit 6.

The operation of the circuit shown in FIG. 3 will be described. The tuner 2 is controlled by a channel selection circuit 9, and tunes to a specific frequency with respect to the signal from the antenna 1 to receive the signal of a desired channel. The video signal detected by the signal processing circuit 3 is normally supplied to the CBr 4 via an amplifier circuit 4 and a selection circuit 6 for display.

The tuning circuit 9 reads data of a predetermined channel from the memory 10 based on key operations from the key input circuit 11 and controls the tuner 2. Writing (presetting) data to the memory 10 is performed as follows. It is done as follows. This will be explained with reference to the flowchart in FIG.

When presetting, the key input circuit 11 instructs the channel selection circuit 9 to start memory operation.

A switching signal is supplied to the signal selection circuit 5, and the fixed signal from the signal generation circuit 7 is switched to be supplied to the CBr 4 (step 1). Thereafter, a channel up operation is performed to receive another channel (step 2). In this state, it is determined whether or not there is a broadcast signal based on the output of the signal detection circuit 8 (step 3), and if there is a signal, the data of that channel is stored in the memory 10 (step 4), and if there is no signal, it is determined that there is a broadcast signal (step 3). The fact that there is no signal is memorized (step 5). The process is executed for all channels in this way, and when the process for all channels is completed, the switching signal to the signal selection circuit 5 is released (step 6.7), and the output of the amplifier circuit 4 is switched to lead to the CBr4. In this way, the memory operation timer is set at this preset time.
The reason why a fixed signal is supplied from the signal generation circuit 7 to the CBr4 is that during memory operation, all channels are received regardless of the presence or absence of a signal, and this is to prevent screen distortion when there is no signal. . By supplying this fixed signal, CR
, T6, for example, a single screen of a specific color is displayed, and it is possible to prevent noise from occurring on one screen.

The signal detection circuit 8 detects the presence or absence of a synchronizing signal, for example, and outputs a "High" signal when a synchronizing signal is present, and a "Low J" signal when there is no synchronizing signal.

Upon receiving this output, the channel selection circuit 9 determines the channel on which the signal is present.

(Problems to be Solved by the Invention) In the above-described channel selection device, a fixed signal is always supplied to CBr4 while memory operation is being performed, so the user can check the output of amplifier circuit 4 in this state. Therefore, the present invention solves the above-mentioned drawbacks and makes it possible to inform the user of the reception status. An object of the present invention is to provide a channel selection device that prevents screen disturbances when there is no signal.

[Structure of the invention]

(Means for Solving the Problems) The present invention utilizes the output from the signal detection circuit during memory operation to control the signal selection circuit for channels with signals so that video signals are supplied to CR and T. For channels with no signal, fixed signals from the signal generation circuit are supplied to cR and T.

(Function) In the present invention, when there is no signal in the output of the signal detection circuit, a specific image based on a fixed signal is displayed on the CRT, and when there is a signal, an image based on the video signal of that channel is displayed on the CRT.
It will be displayed on RT.

(Embodiment of the Invention) An embodiment of the present invention is shown in FIG. The difference in FIG. 1 from the conventional FIG. 3 is that a signal switching control circuit 12 is provided. This signal switching control circuit 12 is supplied with the output from the signal detection circuit 8 and the switching signal from the 2-channel selection circuit 9, and outputs a 1 selection switching signal. A specific example of the circuit is shown in FIG. It shows.

In FIG. 2, the output of the signal detection circuit 8 is supplied to a terminal 21, and a logic "1" signal is applied when a signal is present, and a logic "0" signal is applied when a signal is absent. In addition, a switching signal from the tuning circuit 9 is supplied to the terminal 22;
At the time of presetting, a signal of "1" is added. The terminal 21 is connected to the first input terminal of the AND circuit 25 via the inverter 24, the terminal 22 is connected to the second input terminal of the AND circuit 25, and the output terminal of the AND circuit 25 is connected to the output terminal 23. . This output terminal 23 is connected to the control section of the signal selection circuit 5.

The signal selection circuit 5 is configured so that the output of the output terminal 23 is, for example, "
1”, the signal from the signal generation circuit 7 is CR, T6
When it is "0", the signal from the amplifier circuit 4 is CR
It is switched to lead to T6.

Note that the configuration other than the switching signal control circuit 12 in FIG. 1 is the same as that in FIG. 3, so a detailed explanation will be omitted.

To explain the operation of the present invention, 2. Normally, a switching signal "0" is supplied from the channel selection circuit 9 to the terminal 22, and a signal "1" representing the presence of a signal is supplied from the signal detection circuit 8 to the terminal 21. As a result, the power of the AND circuit 25 is “
0", and a selection switching signal of "0" is generated at the output terminal 23.

The signal selection circuit δ is switched to guide the output of the amplifier circuit 4 to the CRT 6.

Next, the presetting time will be described. At this time, the switching signal "1" is supplied from the tuning circuit 9 to the terminal 22. On the other hand, from the signal detection circuit 8, when there is a signal, K is the signal "1".
is supplied to terminal 21.

The signal is inverted by the inverter 24, becomes a signal "0", and is applied to the AND circuit 26. Therefore, the output of the output terminal 23 is "
0'', and the signal selection circuit 5 converts the output of the amplifier circuit 4 into CR.
, T6, and an image based on the broadcast signal can be displayed even during presetting. However, when the channel becomes a no-signal channel, the rOJ signal is sent from the signal detection circuit 8 to the terminal 21.
This is inverted by the inverter 24.

Both inputs of the AND circuit 250 become "1", and the output terminal 23
The output of is "1". As a result, the signal selection circuit 5
The fixed signal from the signal generation circuit 7 is switched to be guided to CR and T6, and even during presetting, if there is no signal channel, an image based on the fixed signal is displayed on CR and T6, preventing screen disturbances due to noise etc. .

Thus, according to one aspect of the present invention, at the time of presetting.

When the switching signal from the channel selection circuit 9 requests the signal selection circuit 5 to select a fixed signal, if the output of the signal detection circuit 8 is in the state of no signal, the fixed signal is CR,
'! 6, and when there is a signal, the amplifier circuit 4
The output is led to CR, T6.

Therefore, even during presetting, when there is a broadcast signal, CR
, reproduce the broadcast signal on T6.

When there is no broadcast signal, a fixed signal can be reproduced to notify the reception status.

Note that the switching signal control circuit 12 is not limited to the configuration shown in FIG. 2, but may be any other circuit as long as it achieves the same effect.

〔Effect of the invention〕

As described above, according to the channel selection device of the present invention, during execution of memory operation (during presetting), it is possible to prevent screen disturbances on CEI and T for non-signal channels, and to prevent screen disturbances on CEI and T for signal channels. In addition, the broadcast signal image can be reproduced on the ILT to inform the user of the reception status, which is useful for improving functionality.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a channel selection device of the present invention. FIG. 2 is a circuit diagram showing an example of a switching signal control circuit used in the device of the present invention, FIG. 3 is a block diagram showing a conventional channel selection device, and FIG. 4 is a flowchart for explaining the operation of FIG. be. 2...Tuner, 3...,...Signal processing circuit. 4... Amplification circuit, 5... Signal selection circuit. 7... Signal generation circuit, 8... Signal detection circuit. 9...Tuition selection circuit, 10...Memory. 11...Key input circuit. 12...Switching signal control circuit. Agent: Patent attorney: Nori Chika (Interview: Hiropricera Uji) 1 Fixed signal selection 1 Normal 0 Figure 2

Claims (1)

[Claims] A tuner for selectively receiving broadcast signals, a first circuit for detecting and amplifying the received signal, and a second circuit for generating a fixed signal, the first circuit and the first circuit for generating a fixed signal. a signal selection circuit for selecting one of the signals from the second circuit and guiding it to a display device; a memory for storing channel data; and a channel selection circuit; and controlling the tuner to select a desired channel. a signal detecting circuit connected to the first circuit and detecting the presence or absence of a received signal; and a signal detecting circuit that detects an output state of the signal detecting circuit at the time of presetting to write predetermined channel data in the memory. means for switching and controlling the signal selection circuit so that the output of the first circuit is guided to the display device when there is a signal, and the output of the second circuit is guided to the display device when there is no signal. A channel selection device consisting of: