JPH0683432B2 - Television signal response device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a television signal response device used in a digital television receiver or the like.

[Technical background of the invention and its problems]

There are various television broadcasting systems that have more than 525 scanning lines (NTSC) or 625 scanning lines (PAL) in one frame, a frequency bandwidth of more than 4.2 MHz, and more than 20 MHz. Being developed. 1 in Japan
The number of scanning lines in a frame has been developed to 1125, which is about twice the number of current 525 lines. Hereinafter, as an example of a high-definition video signal, one having 1125 scanning lines is referred to as a high-definition video signal, and a video signal according to the current method is referred to as a standard method video signal.

In order to transmit a high-definition video signal as a broadcast signal, a transmission band exceeding 20 MHz in the baseband is required.As a transmission method for broadcasting such a wideband signal with high quality and on a nationwide scale, the FM signal is used. The method of transmitting the data by satellite relay is regarded as promising. However, since the frequency band of Japanese broadcasting satellites is 27 MHz per channel, band compression is indispensable for transmitting a wideband signal such as a high definition television signal by one channel. As described above, as an example of a technique for transmitting a high-definition television signal by one channel by satellite broadcasting, there is a MUSE system developed by NHK (Japan Broadcasting Corporation) and presented in a paper.
[Ninomiya, Otsuka et al. "Satellite 1 channel transmission system (MUSE) for high-definition television" Technical Report of the Television Society. 1984 11
Month] When high-definition television broadcasting by the MUSE system as described above is started via broadcasting satellites, black and white television broadcasting and color television broadcasting were broadcast on the same channel in time division As described above, it is assumed that the standard system broadcast and the MUSE system broadcast will be performed in a time division manner.

At present, a television receiver capable of supporting both standard system broadcasting and MUSE system broadcasting as described above has not been realized yet.

Here, when considering a television receiver capable of receiving both standard system broadcasting and MUSE system broadcasting and displaying an image, a switch for switching between a reception mode and a signal processing mode is naturally required. In other words, the standard system broadcast reception and MU
A switch is required to select the SE system broadcast reception status.

When such a reception state changeover switch is provided, if the switch is manually operated, the operation of the switch is troublesome. This is because, as described above, since the standard method and the MUSE method are performed on one channel in a time-division manner, it is necessary to judge at what point in time the method has been switched, by looking at the screen. Further, although the system has not been switched, the user may erroneously determine that the system has been switched when the broadcast is temporarily interrupted. Furthermore, it may be mistakenly recognized as a failure of the television receiver due to the user's misjudgment.

[Object of the Invention]

The present invention has been made to cope with the above situation, and a television signal that automatically determines and responds when a standard television signal is received and when a television signal is received by high-definition television broadcasting. An object is to realize a response device with a relatively simple configuration.

[Outline of Invention]

The present invention achieves the above object by taking out the synchronous / asynchronous state signal S1 from the phase locked loop circuit 120 and utilizing it, as shown in FIG.

Example of Invention

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. The input section 11 is supplied with a video signal V1 received by a tuner and subjected to detection processing. The video signal V1 is supplied to the high-definition video signal processing unit 12 and a phase-locked loop (hereinafter referred to as PLL) circuit 120 included therein. Further, the video signal V1 is also supplied to the standard system video signal processing unit 16.

The PLL circuit 120 has a system clock (SCK) inside the receiver.
Playback and horizontal sync signal (HS) and vertical sync signal (VS) are the main functions.

A PLL circuit is also used in the current standard system television receiver to perform synchronization separation. However, the PLL circuit inside the standard TV receiver is
If it gets worse, it will not work correctly. If you give a numerical example, the malfunction of the PLL circuit inside the standard television receiver becomes noticeable at S / N of 20 dB.

On the other hand, in the MUSE system, a synchronization format called positive polarity digital synchronization is adopted, and strictly defined frame pulses and horizontal synchronization waveforms (HD) are used as synchronization signals as shown in FIG. FIG. 5 shows the waveforms of the frame pulses inserted in the 605th and 606th lines and the HD waveform (enlarged).

The PLL circuit of the MUSE type television receiver that adopts such a synchronization method can obtain phase lock with extremely high accuracy and is also resistant to noise. Therefore, the S / N of the input signal is 20d
Even in B, a stable phase lock state can be obtained.

In the high-definition video signal processing unit 12, the video signal processing (for example, data interpolation) transmitted by the MUSE method is performed, and the output video signal is supplied to the signal switching unit 13.

On the other hand, in the standard system video signal processing unit 16, the same processing as the video signal processing of the current broadcasting is performed, and its output is
It is supplied to the scan line converter 17. This is necessary because the number of scanning lines of the standard video signal is 525 and the aspect ratio is 4: 3.
On the other hand, since the number of scanning lines of the high definition video signal is 1125 and the aspect ratio of the high definition display 14 is 5: 3, the output of the standard system video signal processing unit 16 is directly increased. This is because a normal image cannot be obtained even if input to the display for quality. Therefore, the scan line converter 17
Is to convert 525 scanning lines into 1125 scanning lines by an interpolation process and also to convert the aspect ratio from 4: 3 to 5: 3. This type of converter is disclosed, for example, in "Izumi, Kokubu et al.," MUSE-type receiving standard adapter ", Television Society Technical Report, September 1984".

Here, the signal switching unit 13 as the response means is configured by the video signal V11 from the high-definition video signal processing unit 12 or the scanning line converter 17
One of the video signals V21 from the
Select in response to the asynchronous state signal S1. The synchronous / asynchronous state signal S1 is, for example, at the high level "H" in the synchronous state and at the low level "L" in the asynchronous state. PLL circuit 1
2 is provided with means for sampling, for example, synchronization data, configuring a phase synchronization circuit by the sampling output, and detecting a synchronization / asynchronous state signal by the phase relationship between the synchronization signal generated by itself and the input synchronization signal. Has been. Further, the synchronous / asynchronous state signal S1 is also supplied to the indicator 15 as a response means. The display unit 15 has a power supply terminal 151, a light emitting element 152, and an inverter 153 when the synchronous / asynchronous state signal S1 is at a high level “H” (during MUSE system broadcasting).
And the current flows and the light is turned on. Further, when the synchronous / asynchronous state signal S1 is at the low level "L", the display 15 is turned off. Therefore, the signal switching unit 13 is
When 15 is lit, the video signal V11 is selected and supplied to the high-definition display 14, and when the display 15 is off, the video signal V21 is selected and supplied to the high-definition display 14. become.

Therefore, according to the above-described television receiver of the present invention,
The standard system broadcast time and the high-definition television broadcast time are automatically determined, which system is displayed on the display 15, and the video signal supplied to the display 14 is also automatically selected. Become.

FIG. 2 shows another embodiment of the present invention. This example
This is the case where the standard display 20 is used as the display. The difference from the embodiment shown in FIG. 1 is that the number of scanning lines of the output video signal of the high-definition video signal processing unit 12 is 1125.
The scanning line converter 21, which converts the book to 525 lines and the aspect ratio from 5: 3 to 4: 3, is provided between the high-definition video signal processing unit 12 and the signal switching unit 13, and the standard system video That is, the output video signal of the signal processing unit 16 is directly supplied to the signal switching unit 13.

In the above-described embodiment, the synchronous / asynchronous state signal S1 obtained by the PLL circuit 120 is used as the control signal of the signal switching unit 13, but in order to obtain a more reliable and stable operation, it is configured as described below. It may be.

The embodiment shown in FIG. 1 and FIG.
The asynchronous state signal S1 was directly used as a control signal for the signal switching unit 13. Normally, when the C / N of the signal input to the receiver is good, the PLL circuit 120 operates stably and always outputs the level “H” indicating the synchronization state. However, the C /
If N becomes very bad, the locked state of the PLL circuit 120 may be established or collapsed. That is, the synchronous state and the asynchronous state are repeated irregularly, and accordingly, the selected state of the signal switching unit 13 is frequently switched. However, in this case, even if the C / N is bad, the PLL circuit 120 requires a certain lock state (at the time of receiving a high-definition television signal including a digital synchronization signal, for example, a MUSE system signal). Therefore, the signal switching unit 13 should also consistently select the high quality video signal processing unit 12 side. C / N
If the signal switching unit 13 makes an incorrect selection due to
The displayed image is corrupted.

Therefore, when C / N is bad, it is necessary to take measures to stabilize the selected state of the signal switching unit 13.

FIG. 3 shows an embodiment in which the above problems are solved. That is,
The same parts as those of the embodiment of FIG.
In the case of this embodiment, the synchronous / asynchronous state signal S1 from the PLL circuit 120 is once supplied to the decision circuit 30 and the decision circuit 30
Therefore, even if the C / N is bad, the switching control signal S2 is not easily affected.
I am trying to make.

FIG. 4 is an example of the determination circuit 30. Input terminal 31
Further, the synchronous / asynchronous state signal S1 from the PLL circuit 120 is supplied. The terminal 31 is connected to the up / down switching terminal of the up / down counter 32. Furthermore, the initial data set terminals (A, B, C, D) of this up-down counter 32
Is given fixed initial data, for example, “ABCD = 0001”. When a load pulse is applied to the load terminal of the up / down counter 32, initial data "ABCD = 0001" appears at the output terminals "OA, OB, OC, OD".

Now start up / down counter as above
In 32, assuming that the terminal 31 is at a high level, that is, a signal indicating the synchronization state is input, the counter 32
Count up the clock (CK). And, "OA ~
When “OD = 1111”, this is detected by the all “1” detector 33, and the detected pulse is detected by the J of the flip-flop circuit 35.
Supply to the input terminal. Therefore, the flip-flop circuit 35
Output becomes high level "H", and the signal at the output terminal 36 indicates that the MUSE system is being received.

On the other hand, when the up / down counter 32 starts, if the terminal 31 is at the low level, that is, the signal indicating the asynchronous state is input, the countdown operation of the initial data “A to D = 0001” is obtained. Then, when the outputs "OA to OD" become all "0", a detection pulse is obtained from the all "0" detector 34, and this is supplied to the K input terminal of the flip-flop circuit 35. Therefore, the Q of the flip-flop circuit 35
The output becomes low level "L", and the signal at the output terminal 36 indicates that the standard system is being received.

The OR circuits 38 and 39 and the inverter 40 perform the following operations. That is, when the detection pulse DP1 is obtained or when the detection pulse DP2 is obtained, the up-down counter 32 is returned to the initial state and the initial data is preset. However, at this time, the current state of the flip-flop circuit 35 does not change just because the up-down counter 32 is preset. Further, as signals for initializing the up / down counter 32, there are an initial signal when the system power supply supplied from the terminal 41 is turned on and a channel switching pulse obtained when the channel supplied from the terminal 42 is switched. .

Therefore, according to this determination circuit 30, even if the synchronous / asynchronous state signal S1 given to the terminal 31 is frequently switched due to the poor C / N described above, the initial data "A ... The period in which "D" finishes counting is a dead zone period. As a result, the selection operation of the signal switching unit 13 becomes stable and reliable even when C / N is poor.

The present invention has been described in the above embodiment as a compatible television receiver capable of supporting high-definition television broadcasting and standard system broadcasting. However, it is needless to say that the present invention is not limited to this, but can be applied to compatible video tape recorders and video disk systems. That is, by adopting the present invention in the signal recording system and the signal reproducing system, it is possible to obtain a highly reliable video processing with a wide range of use.

Furthermore, the present invention is effective in obtaining a reduction in the power supplied to the system, and can obtain accurate switching information.

That is, if the PLL circuit 120 and its signal supply stage are operating, it is possible to determine whether it is the MUSE system reception state or the standard system reception state. Therefore, when a television receiver, a video tape recorder, a video disk system, etc. are used in combination, the above-mentioned sync / asynchronous state signal or the output of the judgment circuit is used with an unused circuit block or device. It can be used as power on / off information for a circuit block or a device. Furthermore, when using a video tape recorder dedicated to the MUSE system and a video tape dedicated to the standard system to obtain continuous recording of MUSE system signals and standard system signals, information for automatically selecting the device and turning the power on and off The determination signal according to the present invention can be used as

In terms of resolution, there is a broadcasting system intermediate between standard system broadcasting and the high-definition television broadcasting, and a broadcasting system in which digital signals are used for synchronization signals and luminance signals and color signals are time-division multiplexed. One example is MAC (Multiplexed Analogu
e Component) method. In the MAC method, since digital data is used for the synchronization signal, stable synchronization can be obtained,
The gist of the present invention can be achieved. That is, with standard broadcasting
It can be easily inferred that the present invention can be implemented in the case where MAC broadcasting is mixed.

In the present invention, the synchronous and asynchronous state signals are produced from the high-definition video signal having the stable synchronization signal, but conversely, the performance of the standard system phase locked loop circuit is enhanced from the current system even from the standard system video signal. By doing so, it can be easily inferred that the present invention can be implemented with the performance according to the present invention by generating the synchronous and asynchronous state signals.

〔The invention's effect〕

As described above, according to the present invention, it is possible to obtain a detection signal capable of identifying television signals of different systems with a relatively simple configuration.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIGS. 2 and 3 are circuit diagrams showing other embodiments of the present invention, and FIG. 4 is a concrete example of the decision circuit of FIG. The circuit diagram shown in FIG. 5 is an explanatory diagram of a sync pulse of a high definition television signal. 12 …… High-definition video signal processing section, 13 …… Signal switching section, 14
...... Display, 15 …… Display, 16 …… Standard system video signal processing unit, 17 …… Scan line converter, 120 …… Phase locked loop circuit.

Claims (7)

[Claims] 1. A standard system video signal processing unit for processing a standard system television signal to obtain a standard system video signal, and a high quality video signal processing unit for processing a high quality television signal to obtain a high quality video signal. A phase-locked loop circuit for reproducing a horizontal synchronization signal, a vertical synchronization signal, and a system clock in synchronization with the synchronization signal of the high-definition television signal in the high-definition video signal processing unit; Of detecting the synchronous state and the asynchronous state of, and in response to the output of the detecting means, when the phase-locked loop circuit is in the synchronous state, and when the phase-locked loop circuit is in the asynchronous state, the response form is A television signal response device comprising a response means for switching. 2. The response means is an indicator to which the output of the detection means is supplied and which switches the light emission state between the synchronous state and the asynchronous state. Television signal response device. 3. The response means receives the output of the detection means to a control terminal, introduces the output of the high-definition video signal processing section to the display in the synchronous state, and the standard system in the asynchronous state. The television signal response device according to claim 1, further comprising means for introducing the output of the video signal processing unit into the display. 4. The display is a high-definition display, and the means for introducing the output of the standard video signal processing unit to the display includes a first scanning line converter, and through this, The television signal response device according to claim 3, wherein the television signal response device is incorporated in the display. 5. The display is a standard system display, and the means for introducing the output of the high-definition video signal processing unit to the display includes a second scanning line converter, and through this, The television signal response device according to claim 3, wherein the television signal response device is incorporated in the display. 6. The response means replaces the period in which the output of the detecting means indicates the synchronous state and the period in which the output indicates the asynchronous state with the count data, and the one having a larger amount of the count data is in a certain cycle. The television signal response device according to claim 1, further comprising circuit means for obtaining a determination result. 7. The response means is means for turning off the power supply of the standard system video signal processing unit when the output of the detection means indicates the synchronization state. A television signal response device according to the item.