JP3022236B2 - Signal discriminator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input signal discriminating apparatus.

[0002]

2. Description of the Related Art To determine whether a signal recorded on a video tape is a PAL system or an NTSC system, a capstan pulse (capstan FG) between control pulses is counted by a counter.
The determination is made.

On the other hand, in order to determine whether a signal received by a tuner or a signal obtained from an external video signal source is a video signal, the number of horizontal synchronizing signals within a certain period is determined by another counter. Counting is performed by a counter, and if the number is equal to or greater than a predetermined value, it is determined that there is a video signal, that is, it is determined to be a station.

[0004]

As described above, the conventional method has a disadvantage that a counter must be prepared for each determination.

Accordingly, an object of the present invention is to solve such a problem.

[0006]

According to the present invention, there is provided a local discrimination means for discriminating the presence or absence of a video signal input from a tuner or from the outside by counting the number of synchronization signals present in the video signal. And a recording signal type discriminating means for discriminating a signal method pre-recorded on the video tape by counting the number of capstan pulses existing between the reproduction control signals. This is a signal discriminating device configured to perform a counting operation by one counter.

[0007]

According to the above arrangement, the synchronization signal obtained for the determination of the station and the capstan pulse used for the determination of the recording signal system are counted by one counter.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of a VTR (video tape recorder) embodying the present invention. A signal caught by an antenna 1 is processed by a tuner / IF circuit 2, which is processed here. The signal is supplied to the next-stage recording / reproducing circuit 3 and the separated horizontal synchronizing signal H
S is supplied to a microcomputer (microcomputer) 5. At the time of recording, a recording signal is supplied from the recording / reproducing circuit 3 to the rotary head 4 and recorded on the magnetic tape T. At the time of reproducing, a reproduced signal reproduced from the magnetic tape T by the rotary head 4 is supplied to the recording / reproducing circuit 3. . The microcomputer 5 issues a command to the servo circuit 6, and the servo circuit 6 servo-controls the rotary head 4 and the capstan 7.

At the time of reproduction, a capstan FG (CFG) signal obtained from the capstan 7 is supplied to the microcomputer 5. A control (CTL) signal obtained at the time of reproduction is input to the microcomputer 5.

FIG. 2 is a detailed functional block diagram of the microcomputer. The horizontal synchronizing signal HS is connected to a terminal 16 by a CF.
The G signal is input to a terminal 17 and the CTL signal is input to a terminal 18.

The horizontal synchronizing signal or CFG signal is input to a counter 10 via a changeover switch 9. The count value of the counter 10 is input to the locality discriminating unit 12 and the tape type discriminating unit 13, and the locality discriminating unit 12 outputs a locality discriminating signal to the main 15 and the tape type discriminating unit 1
3 outputs an NTSC / PAL discrimination signal based on the value of the counter 10 and the control pulse. At the time of tuning selection, the main control unit 15 gives data (data indicating broadcast existence) based on the occupancy discrimination signal to the tuning frequency best point finding unit 14, and the finding unit 14 uses this data as preset information. Store. And the main tuning section 1
Reference numeral 5 indicates a mute signal for muting audio and video output from the terminal 19 to the recording / reproducing circuit 3 when the user selects a non-owned channel during normal channel selection.

The main control unit 15 is provided with an NTSC
A / PAL switching signal is output from the terminal 20 to the recording / reproducing circuit 3.

On the other hand, the main control unit 15 supplies a signal (reproduction state signal) indicating whether or not the VTR is in a reproduction state to the occupancy determination unit 12 and the tape type determination unit 13. The occupancy determining unit 12 and the tape type determining unit 13 control the changeover switch 9 based on the reproduction state signal and take in the count value of the counter 10.

In the present embodiment, the locality discriminating unit 12, the tape type discriminating unit 13, the main unit 1
5 is a program R incorporated in the one-chip microcomputer
The other components are configured by hardware of the microcomputer 5.

Next, the operation of the tape type discriminating section will be described with reference to FIG.

The tape type determining section 13 first determines whether a control pulse has been input (S
1). If it is determined in step 1 that a control signal has been input, it is next determined whether or not the VTR is in a playback state (S2).

Next, when it is determined in step 2 that the reproducing state is set, it is determined whether or not the changeover switch 9 is on the horizontal synchronizing signal side (S3). Side (S
8) The count value of the counter 10 is set to 0 (reset). If it is determined in step 3 that the changeover switch 9 is on the CFG side, the counter value of the counter 10 (the count value is the number of CGF pulses between control pulses) is input to the tape type determination unit 13 (S4). ),
The counter 10 is reset (S5). Next, from the count value obtained from the counter 10, it is determined whether the signal recorded on the tape is recorded by the PAL system or recorded by the NTSC system (S6).
An NTSC determination signal is output (S7). Then, the main unit 15 receives this and outputs a PAL / NTSC switching signal (N / P) from the terminal 20.

Next, a description will be given of the operation of determining whether or not a station is located with reference to FIG.

The occupancy determining section 12 first determines whether or not 1 millisecond (mSec) has elapsed since the previous occupancy determination operation (S11). If it is determined in step 11 that 1 millisecond has elapsed, then it is determined whether or not the VTR is in the non-reproduction state (S12). If it is determined in step 12 that the playback mode is the non-reproduction state, and if it is determined in step 13 that the switch 9 is on the CFG side, the switch 9 is switched to the horizontal synchronization signal side (S18), and the counter The value is reset (S19). If it is determined in step 13 that the signal is on the horizontal synchronizing signal side, the counter value of the counter 10 is input to the locality determination unit (S1).
4), the counter 10 is reset (S15). next,
From the count value obtained from the counter 10 (the count value is the number of horizontal synchronization signals counted in the above 1 millisecond), it is determined whether or not there is a broadcast signal from a broadcast station (station determination). This is performed (S16), and an occupancy determination signal is output (S17). Then, the main unit 15 receives this and outputs an AV mute signal (AVMUTE).

Thus, step 2 and step 1
As a result of 2, the counting operations by the counters for the locality determining unit and the tape type determining unit do not overlap in time.

[0022]

As described above, according to the present invention, the synchronization signal obtained for determining the presence of a station and the capstan pulse used for determining the recording signal system are counted by one counter. Therefore, the configuration can be simplified, which greatly contributes to cost reduction.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a video tape recorder embodying the present invention.

FIG. 2 is a block diagram showing a main part of FIG. 1 in detail.

FIG. 3 is a flowchart illustrating a tape type determination operation.

FIG. 4 is a diagram illustrating a flowchart for explaining an occupancy determination operation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Tuner / IF circuit 3 Recording / reproducing circuit 4 Rotating head 5 Microcomputer 6 Servo circuit 7 Capstan 8 Control head 9 Changeover switch 10 Counter 11 Timer circuit 12 Ownership determination part 13 Tape type determination part 15 Main part

Claims (3)

(57) [Claims] 1. An organic identification means for identifying the presence or absence of a video signal input from a tuner or from the outside by counting the number of synchronization signals present in the video signal, Recording signal type discriminating means for discriminating the signal method by counting the number of capstan pulses existing between the reproduction control signals, wherein the locality discriminating means and the recording signal discriminating means perform a counting operation by one counter. A signal discriminating device configured as described above. 2. The apparatus according to claim 1, wherein said locality discriminating means and said recording signal type discriminating means are constituted by microcomputer software.
2. The signal discriminating apparatus according to claim 1, wherein said counter is constituted by hardware of a microcomputer. 3. When the counter is counting one of a horizontal synchronizing signal and a capstan pulse,
3. The signal discriminating apparatus according to claim 2, wherein the other counting is not performed.