JPH02235244A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To enable meaningless reproducing or image recording in a non-signal state by counting a non-signal state continuing time, and after the end of counting of a previously set counting time, switching between the output of a pattern and the output of a receiving signal. CONSTITUTION:When a non-signal state having no receiving signal or control signal is detected, a main control signal 3 outputs a pattern selecting signal and an output switching signal based upon an output from a non-signal detecting circuit 17 and a mode signal from an operation mode control circuit 10 and outputs also a count start signal. A pattern generating circuit 4 outputs a pattern corresponding to each operation mode and an output switching means 9 is switched to the pattern output signal side to output the pattern. The pattern screen is continuously outputted up to the end of the counting time previously set up by a timer circuit 11, and after the end of counting, releases the operation mode. Consequently, the generation of meaningless reproducing or image recording in the non-signal state can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording and reproducing apparatus that prevents meaningless reproduction, recording, etc. in a no-signal state.

[Conventional technology]

When a video table recorder (hereinafter referred to as a VTR device) is used as a magnetic recording and reproducing device, if you play back a section with no signal or select a channel other than the designated channel of the broadcasting station, unpleasant images may appear on the screen of the television receiver. Noise or noisy audio occurs.

To prevent this, a blue back method as shown in FIG. 2 is conventionally known. This method will be explained as follows.

During recording and other operating modes, the received signal from the receiving antenna 30 is input to the received signal detection circuit 32 via the tuner circuit 31, and the presence or absence of the received signal is detected. Further, in the reproduction mode, the control signal recorded on the video tape 38 is input to the control signal detection circuit 36 via the reproduction magnetic head 46 and the control signal amplification circuit 37, and the presence or absence of the control signal is detected.

When the main control circuit 33 detects the no-signal state of the above received signal or control signal, the pattern screen generation circuit 3
4, a constant blue color pattern screen output is output regardless of the operation mode, and the output changeover switch 39 for switching between the received signal and the pattern screen output is switched to the pattern output side. Subsequently, the above pattern screen output is output to the television receiver 45, making it possible to recognize the no-signal state.

Incidentally, when the no-signal state of the above-mentioned received signal or control signal is not detected, the above-mentioned output selector switch 39 is switched to the signal processing circuit 35 side, and the output of the tuner circuit 31 is outputted via the signal processing circuit 35. It is output to the television receiver 45.

[Problem to be solved by the invention]

However, in the conventional configuration described above, only one type of pattern screen output is generated when a no-signal state is detected. For this reason, it is difficult to distinguish between playback mode, recording mode, and other operation modes just by looking at the pattern screen output.

Furthermore, if the screen of the television receiver suddenly changes to the above-mentioned pattern screen output while the VTR device is in operation, this is likely to be mistaken as a failure.

Furthermore, if the person operating the VTR device does not notice the above-mentioned pattern screen output or forgets to turn off the power and leaves the VTR device unattended, meaningless playback may occur during the period when no signal continues. Since recording etc. must continue, there are problems such as unnecessary power consumption.

[Means to solve the problem]

In order to solve the above problems, the magnetic recording and reproducing device according to the present invention detects the presence or absence of input of a received signal during recording and other operation modes, and also detects the presence or absence of input of a received signal during the reproducing mode. A no-signal detection circuit detects the presence or absence of a signal, outputs a signal to control the operation of each part of the device for each operation mode, outputs a mode signal corresponding to each operation mode, and cancels the operation mode from a clock circuit. When a command signal is input, the operation mode control circuit outputs a pattern screen stop signal, and when a no-signal state with no received signal or control signal is detected by the above-mentioned no-signal detection circuit, the operation mode control circuit outputs a pattern screen stop signal. An output that outputs a pattern screen selection signal to the pattern screen selection means to instruct selection of the pattern screen output corresponding to the current operation mode based on the mode signal of A main control circuit that outputs a switching signal to the output switching means and also outputs a count start signal to the clock circuit to instruct the start of counting the no-signal state duration time, and a main control circuit that outputs a switching signal to the output switching means and a count start signal that instructs the clock circuit to start counting the no-signal state duration time. a pattern screen selection means for selecting a pattern screen output set for each pattern screen output; a pattern screen generation circuit for generating a pattern screen output selected by the pattern screen selection means;
When the count start signal from the above main control circuit is input, the no-signal state duration time is counted, and after the preset clock time has been counted, an operation mode cancellation command signal is output to the operation mode control circuit. It is characterized by comprising a clock circuit and an output switching means for switching between a pattern screen output and a received signal output when an output switching signal is input from the main egg 1 control circuit.

[For production]

With the above configuration, the presence or absence of a received signal or the presence or absence of a control signal is detected by the no-signal detection circuit and inputted to the main control circuit. Further, a mode signal is input from the operation mode control circuit to the main control circuit.

In each operation mode, when a no-signal state with no received signal or control signal is detected, the main control circuit sends a pattern screen selection signal and an output switching signal based on the output of the no-signal detection circuit and the mode signal. At the same time, it also outputs a count start signal. Then, the pattern screen generation circuit outputs a pattern screen output corresponding to each operation mode in response to the pattern screen selection signal. Further, the output switching means is switched to the pattern screen output side by the output switching signal, and the above pattern screen output is output. This pattern screen output continues to be output until the clock circuit finishes counting the preset clock time. After the time measurement is completed, an operation mode release command signal is output from the time measurement circuit to the operation mode control circuit.

In response to the operation mode release command signal, the main control circuit stops the pattern screen generation circuit from outputting the pattern screen output, and also cancels the operation mode via the operation mode control circuit.

〔Example〕

An embodiment of the present invention will be described below based on FIG.

A video tape recorder (hereinafter referred to as a VTR device) as a magnetic recording/reproducing device mainly includes a no-signal detection circuit 17, a main control circuit 3, and a signal processing circuit 5, as shown in FIG.
, a pattern screen generation circuit 4, an operation mode control circuit 10, and a clock circuit 11. The no-signal detection circuit 17 includes a tuner circuit 1, a received signal detection circuit 2, a control signal detection circuit 6, and a control signal amplification circuit 7, and detects the presence or absence of a received signal or a control signal.

During recording and other operating modes, the received signal from the receiving antenna 14 is input to the tuner circuit l. The output of the tuner circuit 1 is input to a received signal detection circuit 2 and also to a signal processing circuit 5. Same circuit 2
Then, the presence or absence of a received signal is detected. The output of the signal processing circuit 5 is connected to a contact 9a of an output changeover switch 9 as an output changeover means. Further, the output of the received signal detection circuit 2 is input to the main control circuit 3.

Further, in the playback mode, control signals recorded on the video tape 8 as a recording medium are input to the control signal amplification circuit 7 via the magnetic playback head 16, and the output of the circuit 7 is transmitted to the control signal detection circuit 6. has been entered. The circuit 6 detects the presence or absence of a control signal. The output of the circuit 6 is input to the main control circuit 3 mentioned above. moreover,
From the operation mode control circuit 10, a mode signal indicating the selected operation mode and a pattern screen stop signal for stopping the pattern screen display are input to the main control circuit 3. The count start signal from the main control circuit 3 is sent to the clock circuit 1l.
has been entered. The circuit 11 measures the duration of a no-signal state in which there is no received signal or control signal. The operation mode release command signal from the clock circuit 11 is input to the operation mode control circuit 10. In the same circuit 10, the operation of each part of the device is controlled based on the output from the main control circuit 3, and the above-mentioned pattern screen stop signal is output to the main control circuit 3 in response to the operation mode release command signal. A mode signal corresponding to the mode is output to the main control circuit 3.

The output of the main control circuit 3 is connected to a common terminal of a pattern screen selection switch 12 serving as pattern screen selection means. The contacts 12a to 12n of the switch 12 are respectively connected to the inputs of pattern circuits 4a to 4n in the pattern screen generation circuit 4, which output the corresponding pattern screen outputs AN. Further, the outputs of the pattern circuits B4a to B4n are connected together, and the contact 9 of the output changeover switch 9
connected to b. The switch 9 switches between received signal output and pattern screen output.

That is, in the reproduction mode, pattern screen output A is selected, and the output of the pattern circuit 4a is outputted to the television receiver 15 via the output changeover switch 9 as the output of the pattern screen generation circuit 4. Furthermore, in the recording mode, pattern screen output B is selected, and the output of the pattern circuit 4b is output as the output of the pattern screen generation circuit 4 to the television receiver 15 via the output changeover switch 9. Similarly, in other operation modes, pattern screen output C-N is selected for each operation mode, and the outputs of the pattern circuits 4c to 4n are output to the television receiver 15. Incidentally, the common terminal of the output changeover switch 9 is connected to the television receiver l5.

In the above configuration, during recording and other operating modes,
The received signal from the receiving antenna 14 is transmitted to the tuner circuit 1,
The signal is inputted to the television receiver 15 via the signal processing circuit 5 and the contact 9a of the output changeover switch 9. Here, when the received signal disappears, the received signal detection circuit 2 detects a no-signal state, and the main control circuit 3 recognizes this. and,
The main control circuit 3 outputs a count start signal to the clock circuit 11, a pattern screen selection signal to the pattern screen selection switch 12, and an output switching signal to the output changeover switch 9.

The main control circuit 3 recognizes the operation mode based on the mode signal from the operation mode control circuit 10, and causes the pattern screen generation circuit 4 to output a pattern screen output corresponding to each operation mode based on the pattern screen selection signal. Further, the output changeover switch 9 is connected to the contact 9b side by the above output changeover signal, so that each of the above pattern screen outputs is output to the television receiver 15.
is output to.

When the no-signal state continues for a preset clock time or longer, the clock circuit 11 outputs an operation mode release command signal to the operation mode control circuit 10. Based on this signal, the main control circuit 3 causes the circuit 10 to cancel the operation mode, so that recording without a signal and other modes can be stopped.

That is, when there is no signal in the recording mode, pattern screen output B is output. If the no-signal state continues further, a pattern screen stop signal is output from the operation mode control circuit 10 to the main control circuit 3 after the clock circuit 11 finishes counting. Based on this, the circuit 3 stops outputting the pattern screen output B, and also stops the operation mode control circuit lO.
The VTR device is moved to the stop mode via the . Also,
If the no-signal state continues in other operation modes, the output of the pattern screen output C-H is stopped after the clock circuit 11 finishes counting, and the VTR device shifts to the power OFF mode.

Similarly, in the reproduction mode, the control signal recorded on the video tape 8 is input to the control signal amplification circuit 7 via the reproduction magnetic head l6. The output of the circuit 7 is input to the main control circuit 3 via the control signal detection circuit 6, and the presence or absence of the control signal is recognized. When a state in which there is no control signal is detected, the clock circuit 11 starts counting time, and the pattern screen output A is output from the pattern screen generation circuit 4. Furthermore, if this state continues for longer than the above-mentioned time period, the output of the above-mentioned pattern screen output A is stopped by the main control circuit 3 via the operation mode control circuit 10 after the timing circuit 11 finishes counting, and the VTR device Transition to stop mode.

[Effects of the Invention] As described above, the VTR device according to the present invention detects the presence or absence of input of a received signal during recording and other operation modes, and detects the presence or absence of input of a received signal during playback mode. a no-signal detection circuit that detects the presence or absence of a signal, outputs a signal to control the operation of each part of the device for each operation mode, outputs a mode signal corresponding to each operation mode, and also outputs an operation mode cancellation command from a timing circuit. an operation mode control circuit that outputs a pattern screen stop signal when a signal is input;
When the above-mentioned no-signal detection circuit detects a no-signal state with no received signal or control signal, it commands the selection of pattern double-sided output corresponding to the current operation mode based on the mode signal from the operation mode control circuit. outputs a pattern screen selection signal to the pattern screen selection means, outputs an output switching signal instructing switching between the pattern screen output and the received signal output to the output switching means, and starts measuring the no-signal state duration time. A main control circuit that outputs a commanded count start signal to the timekeeping circuit, a pattern screen selection means that selects a pattern screen output preset for each operation mode based on the pattern screen selection signal, and a pattern screen selection device. When inputting the count start signal from the pattern screen generation circuit that generates the pattern screen output selected by the means and the above-mentioned main control circuit, it measures the no-signal state duration time and also measures the preset time measurement time. A timing circuit that outputs an operation mode cancellation command signal to the operation mode control circuit after timing is completed; and an output switching means that switches between pattern screen output and received signal output when an output switching signal is input from the main control circuit. This configuration has the following features.

As a result, the generated pattern screen output differs depending on the operation mode, so the current operation mode can be reliably determined by looking at the pattern screen output. Furthermore, in each operating mode, if a no-signal state continues for a preset clocked time or longer, each operating mode is canceled after the clocked time has elapsed, making it possible to avoid meaningless playback or recording. Therefore, you can use your VTR with confidence without wasting power.
It also has the advantage of being able to use the equipment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a block diagram showing a conventional example. 2 is a received signal detection circuit, 3 is a main control circuit, 4 is a pattern screen generation circuit, 6 is a control signal detection circuit (no signal detection circuit), 9 is an output changeover switch (output changeover means), 10 is an operation mode control circuit , 11 is a clock circuit, and 12 is a pattern screen selection switch (pattern screen selection means). Patent applicant Sharp Warazu Co., Ltd.

Claims (1)

[Claims] 1. A no-signal detection circuit that detects the presence or absence of a received signal input during recording and other operation modes, and detects the presence or absence of a control signal recorded on a recording medium during playback mode. , Outputs a signal to control the operation of each part of the device for each operation mode, outputs a mode signal corresponding to each operation mode, and also outputs a pattern screen stop signal when an operation mode cancellation command signal is input from the clock circuit. When a no-signal state with no received signal or control signal is detected by the above-mentioned no-signal detection circuit, the operation mode is changed to the current operation mode based on the mode signal from the operation-mode control circuit. Outputting a pattern screen selection signal instructing selection of the corresponding pattern screen output to the pattern screen selection means, and outputting an output switching signal instructing switching between the pattern screen output and the received signal output to the output switching means; A main control circuit that outputs a count start signal to the timing circuit to instruct the start of counting the no-signal state duration time, and a pattern screen output that is preset for each operation mode based on the pattern screen selection signal described above. A pattern screen selection means, a pattern screen generation circuit that generates a pattern screen output selected by the pattern screen selection means, and a count start signal from the above-mentioned main control circuit are input, and the no-signal state duration time is measured. In addition, there is a timing circuit that outputs an operation mode cancellation command signal to the operation mode control circuit after a preset clock time has finished, and a pattern screen output and reception signal when an output switching signal is input from the main control circuit. 1. A magnetic recording and reproducing device comprising: output switching means for switching between outputs.