JPH03793Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field to which the invention pertains] The present invention relates to a video signal reproducing device that uses a delayed signal obtained from a delay element with an intermediate terminal for multiple purposes and has a simplified signal processing circuit. .

[Description of prior art]

Conventionally, delay elements have been used as elements to delay a certain signal for a certain period of time, and commonly known elements include CCD, BBD delay elements,
There are glass delay elements, etc. Such a delay element is
It is used in video signal processing circuits that require many delay circuits. For example, the R-Y signal, B-
If we consider a recording/reproducing device that records video signals with line sequential color difference signals such as a Y signal on a magnetic medium, we will see that there are R-Y signals, B-
A circuit for simultaneously outputting Y signals every 1H,
A delay element is required in a field/frame conversion circuit or the like that converts a field signal into a frame signal.

Figure 1 shows the R-Y signal and B- signal alternately every 1H.
1 is a configuration block diagram showing a conventional example for synchronizing line sequential color difference signals in which a Y signal appears every 1H; FIG.

Line sequential color difference signals have R-Y and B-Y signals only every 1H, so for example, in 1H where there is no RY signal, the RY signal of the previous 1H is delayed by 1H, and the B-Y signal is delayed by 1H. The -Y signal and the RY signal are simultaneously outputted, and the BY signal and the RY signal are simultaneously outputted in the same way even in 1H where there is no BY signal.

That is, in FIG. 1, the line sequential color difference signal applied to input terminal 1 is as follows:
1HDL and is also input to switches 2 and 3. The switches 2 and 3 alternately switch the signal from the input terminal 1 and the 1H delayed signal passed through the 1HDL 6 every 1H by the drive pulse from the drive circuit 7, and take it out to the output terminals 4 and 5. ,
A RY signal and a BY signal are continuously obtained at each output terminal 4 and 5, respectively.

FIG. 2 is a block diagram showing a conventional field/frame conversion circuit for converting a field repetition signal into a frame signal.

For frame signals, it is necessary to provide a signal shift of 0.5H between odd and even fields. Therefore, in this circuit, the field signal from input terminal 8 is delayed by 0.5HDL11, and this
The signal from the 0.5HDL 11 and the field signal applied to the input terminal 8 are switched for each field by a switch 9 driven by a drive circuit 12, so that an output signal (frame signal) is obtained at the output terminal 10. I have to.

In this way, video signal processing circuits require many delay circuits, and if a delay element is used for each circuit, many delay elements are required for the entire circuit, making the circuit complex and the component cost high. There were flaws.

[Purpose of this invention]

The present invention was developed in view of these shortcomings, and aims to reduce the number of components, simplify the circuit, and reduce costs by using a delay element with an intermediate output terminal for multiple purposes. shall be.

[Explanation of Examples]

FIG. 3 is a block diagram showing an example of a CCD delay element having an intermediate output terminal used in the present invention. In this example, 455-bit CCD1
It is constructed by continuously connecting 5 and 16 in two stages.
The signal applied to input terminal 13 is 455 bits.
The signal delayed through the CCD 15 is output from the intermediate output terminal 18, and each CCD 15, 1
6 (910 bits in total) is output from the output terminal 17.

Here, the clock signal for driving each CCD 15, 16 is applied to the terminal 14, and this clock is applied to the NTSC color subcarrier frequency fsc (3.58M
Hz), a signal delayed by 1H is obtained from the intermediate output terminal 18, and a signal delayed by 2H from the output terminal 17 is obtained. Furthermore, if the clock signal applied to the terminal 14 is 4·fsc, then the intermediate output terminal 1
A signal delayed by 0.5H is obtained from the output terminal 8, and a signal delayed by 1H is obtained from the output terminal 17.

FIG. 4 is a block diagram showing an example of a circuit according to the present invention, which includes both the circuit for synchronizing color difference signals every 1H shown in FIG. 1, and the field frame conversion circuit shown in FIG. It has the following functions.

That is, in FIG. 4, switches 25, 2
6 (first switch means) and 1HDL21, 27
A circuit is configured to simultaneously output the R-Y signal and the B-Y signal every 1H, and the switches 22 and 29
(second switch means) and 1HDL 21, 27 constitute a field frame conversion circuit.

In this circuit, one delay element is used for each of the R-Y signal and the B-Y signal, and 1HDL2
1 and 1 HDL 27 both have intermediate output terminals 20 and 28 shown in FIG.

In FIG. 4, the input terminal 19 is connected to the R-Y signal and the B signal output from the recording medium alternately every 1H.
A video signal (field signal) including a color difference signal such as a -Y signal is applied. This signal is input to switches 25 and 26. These switches 25 and 26 are switched by drive pulses from the drive circuit, and the switch 25 switches the video signal from the input terminal 19 and the 1H delayed signal passed through the 1HDL 21 every 1H, and 2
2. Similarly, the switch 26 receives the video signal from the input terminal 19 and passes through the 1HDL 27.
Switch 1H delay signal every 1H, switch 29
input.

On the other hand, intermediate output terminal 2 of each 1HDL21, 27
From 0.28, a 0.5H delayed signal is obtained,
It is input to switches 22 and 29. The switches 22 and 29 are switched by drive pulses from the drive circuit 30, and the switch 22 is
The signal taken out by the switch 25 and the 0.5H delayed signal from the intermediate output terminal 20 are switched and taken out for each field. Similarly, the switch 29 receives the signal taken out by the switch 26 and the intermediate output terminal 28.
The 0.5H delay signal from the 0.5H delay signal is switched and extracted for each field.

Therefore, from the switches 22 and 29 (from the output terminals 23 and 24), a frame signal containing both the RY signal and the RY signal can be obtained at the same time.

Although a CCD delay element is used as a delay element in the embodiment, it goes without saying that the present invention is not limited to this, and that various delay elements having an intermediate terminal such as a BBD delay element can be applied.

[Effects of this invention]

As explained above, in the past, color difference signals were
1HDL element is 1 in the circuit for synchronizing each
A circuit that converts a field signal into a frame signal, which previously required two 0.5HDL elements, three in total, now has two elements, according to the present invention.
A circuit having both functions can be realized using two delay elements.

Therefore, according to the present invention, the number of expensive delay elements can be reduced, the cost can be reduced, and power consumption can be reduced. Therefore, miniaturization is possible, which is particularly effective in the case of a portable video signal reproducing device.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional circuit for synchronizing color difference signals every 1H, Fig. 2 is a block diagram of a conventional circuit for converting field signals into frame signals, and Fig. 3 is a block diagram of a conventional circuit for converting a field signal into a frame signal. FIG. 4 is a block diagram showing an example of a circuit according to the present invention. 19...Input terminal, 21,27...CCD delay element, 20,28...Intermediate output terminal, 22,2
5, 26, 29... switch, 23, 24... output terminal, 30... drive circuit.

Claims (1)

[Claims for Utility Model Registration] An input terminal for inputting a video signal including a line sequential color difference signal outputted from a recording medium,
A video signal reproducing device having a function of simultaneously outputting to a pair of output terminals every 1H and a function of converting a field signal into a frame signal, comprising two 1H delay elements each having an intermediate output terminal;
A first switching means and a second switching means each consisting of a pair of switching elements are provided, and the first switching means causes one of the switching elements to be connected to one output terminal of the two 1H delay elements. When connected, the other switching element is connected to the input terminal, and when the other switching element is connected to the output terminal of the other of the two 1H delay elements, the one switching element is connected to the input terminal. The pair of signals obtained from the first switching means are branched and input to the two 1H delay elements, respectively, and a pair of 0.5H delay signals are taken out from the respective intermediate terminals. the pair of signals obtained from the first switch means and the two signals obtained by the second switch means;
A pair of 0.5H obtained from the intermediate terminal of a 1H delay element
1. A video signal reproducing device characterized in that it is configured to switch between delayed signals and delayed signals for each field.