JPS5915372A - Converter for number of scanning line - Google Patents

Abstract

PURPOSE:To convert the number of scanning lines, by using three CCDs to write the signal of the 1st scanning system into the CCDs with the writing clock of the 1st frequency by an amount equivalent to one horizontal scan period and then reading out repetitively the written signal with reading clock of the 2nd frequency and at the same time reading excessively by one time if some time difference exists between the writing and the reading. CONSTITUTION:The clocks of fC1 of W-1, 2 and 3 are applied to three CCDs in periods S-1, 2 and 3 respectively, and at the same time each input switch is closed the side of an input A to write the signal of the 1st system. Then clocks of fC2 of R-1, 2 and 3 are applied to the CCDs in periods t-1, 2 and 3, and at the same time an input switch is closed to the output side of the CCD through a buffer. Thus the signals of CCDs of periods t-1, 2 and 3 can be repetitively delivered. If no signal of S or (t) does not exist, the CCD does not write nor read the signal and holds the signal which is written just before disappearance of the signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a scanning line number conversion device for matching the number of scanning lines when receiving two television signals having different horizontal scanning periods.

Conventional configuration and its problems The image transmission method divides the screen horizontally and sends it out.
Basically, the receiving side scans and reproduces the screen in synchronization with the transmitting side. This number of horizontal scans is determined by one transmission method, and it is impossible to reproduce signals with different numbers of horizontal scans.

However, if the currently proposed 1,126-line horizontal scanning high-definition television broadcasting begins, there will be two types of systems in addition to the current NTSC system, and a separate television receiver will be required. Therefore, if the vertical frequencies are the same, it is only necessary to change the number of scans by kF so that the signals scanned at lower horizontal frequencies can be received by a receiver that scans at higher frequencies.

On the other hand, PAL, S
Various format conversion devices for converting to the ECAU format or vice versa have been proposed and are currently being used at broadcasting stations, but these devices require expensive A/me converters, D/A converters, memory, etc. Most of these devices are digital image processing devices, and they are not designed with full consideration for incorporation into commercially available television receivers.

However, when broadcasting in another format such as high-definition television broadcasting is about to begin, a receiver that can also receive NTSC format and high-definition television is required, and the system that can be incorporated into such a receiver is required. One important condition is that the conversion device be inexpensive.

OBJECTS OF THE INVENTION The present invention provides a system conversion device having the necessary performance by using a relatively inexpensive charge transfer device (COD) without using expensive digital elements. Using two CCDs 1, a signal of the first scanning method is written to the COD for one horizontal scanning period using a writing clock of the first frequency, and then read out repeatedly using a clock of the second frequency, and the time difference between them is At certain times, the data is read out one more time to complete the number of scanning lines.

DESCRIPTION OF THE EMBODIMENTS As shown in FIG.
When l〉TH2), THl ” ” TH2+Δt ・=・=−
(11 (n is an integer) 0 Δt<TH2 (2).

In order to convert the signal of the first scanning method (scanning period TH1) to the second scanning method (scanning period "H2"), THl
Compress the entire time of the signal that has been stored in TH2 and rrj
/-1,: Must be L.

When using a CCD, if the number of stages of COD is N, then the writing clock becomes TH.
It is possible to write in 1 ccD for one horizontal scanning period of l. At the time of writing, if A1- is written for the TH1 period, then the clock fc1' is stopped, and then the read clock is read from COD, the signal 'l written in the TH1 period can be read at the time of TH2. can. In this way, it can be used as a C0D-i time compression element.

Hereinafter, for the sake of simplicity, the description will be made assuming that n shown in equation (1) is 2.

As shown in FIG. 3, the signal Ai of the first scanning method
In order to convert to the signal B of the system, the signal written in THl must be read out twice or more.

To read the signal written to COD multiple times,
As shown in FIG. 2, all output buffers of the COD may be passed through and returned to the input again, and data may be written and transferred using the same clock as the read clock fC2.

Now, returning to Figure 3, between the first scanning method and the second scanning method, due to the time difference of Δt, the time at which horizontal scanning starts is not constant, and therefore the signal t written in THl and the time when THl ends. If the signal is read out at fC2 immediately after the signal is read out, the signal will be out of phase with TH2.

For this purpose, the signal must be held for a time Δt1-2 at the trench where TH2 starts immediately after the end of TH1.

When the CCD 1 is used in a normal manner, it functions only as a shift register for analog signals and has no storage function. However, in this device, we focused on the fact that by stopping the transfer lock of the COD, the charge stored inside the COD at that point can be maintained as it is, and when THl is finished, the charge is transferred between Δt1-2. By stopping the clock signals 1- and then reading them using the clock fc2, the signal can be converted regardless of the phase difference between the horizontal cycles of the first method and the second method.

The reason why three CCDs 1, 2, and 3 are required as shown in FIG. 2 is because the above-mentioned operations are required for each COD, so they are written during the entire period of the first method and read during the entire period of the second method. This is because a minimum of three is required to achieve this.

In order to operate these three CCDs, S-1, 2,
W-1, 2, 3 f in period 3. 1 clock to each COD and simultaneously close all input switches to the A side, it is possible to write the signal of the first method, and during periods t-1, 2, 3, R-1°2. 3's
By applying a clock of 1 ccD to fc2 and simultaneously closing the input switch toward the output side of the COD passing through the buffer, each COD signal can be repeatedly output during periods t-1, 2, and 3.

If there are no S and t signals, the CCD retains the most recently written 1 signal without writing or reading the signal.

Now, the period for reading COD with fc2, the minimum is 2
It is necessary to read out the information twice in succession, but in certain conditions, it is necessary to read it out three times.

Taking FIG. 3 as an example, a signal written in CcDl for a period a is read twice in the second method, but a signal written in a period b is read three times in the second method Id. This is the period C after the first period b ends.
During writing on CD3, the horizontal period of the second method starts three times.

The second method starts the next THL from the point where the first method ends.
During this period, the number of times the scan starts is 3 times if the time when the second method scan starts immediately after the first method scan ends is smaller than Δt shown in equation (1). , Δt, or if it is the same, it can be determined that the number of times is twice.

To explain using the circuit shown in FIG. 4 and the time chart shown in FIG. 5, by resetting the time when the first method ends to the time when the second method starts immediately after R5-FFQ, Δt1- Obtain the pulse of time 2. Separately, from the fall of the horizontal frequency fH1 of the first scan (this is the time when one horizontal scan of the first constant scanning method ends), Δt
A pulse Δtl having a time width of Δt1 is generated by a monostable multi-by-recoder, and is synthesized by a Δt1-2 and Δt1 NAND gate to obtain an output Ei only when Δt1-2 is smaller than Δt.

Next, a counter is required to count TR2 two or three times, and after writing is completed during the THL period, it is necessary to determine how many times and which COD output is to be read during the next R2 period.

In order to do this, it is necessary to enable the operation with a rising signal immediately after the period of the counter tTHl ends. To obtain t-1 output, S-2° [-2 output requires S
-3, t-3 outputs are provided with R-8F, F, 19°21.23, which are set by each pulse of S-1, so that it can be determined which CCD will be read out first.

The counter is set to operate at the rising edge of the clock TR2, and when the outputs of R-8F and F are at a high level, it starts counting and outputs at the cycle of TR2.

If this counter is made programmable and the input catator value D-A is changed by the E output mentioned above, TR
At the rising edge of 2, the E output is taken in, and the output is set so that when E is at a high level, it is counted three times, and when E is at a low level, it is counted twice.

If the counters 20, 22.24 and sol carry outputs are used as cent inputs to the R-8F, F, and 19, 21.23 mentioned above, the moment the ripple carry output comes out, it will become a cent and the counter operation will stop. do.

The above contents are explained in the 3rd section. FIG. 6 shows the timing for the second example of COD and COD'i.

The overall configuration will be explained by returning to FIG. 2. In general, a composite signal method and a component method (Y/C or R, G, E) can be considered for color signal transmission, but if the composite signal method is used, the color subcarrier must also be converted, and the method described above cannot be used. It is not possible to convert into A-7 Sora-ji.

In the present invention, as shown in FIG. 2, a two-channel system is adopted, and a method is used in which the luminance signal and the color signal or the two color difference signals are converted into their respective systems.

Of course, it is also possible to convert RGBS colors into three channels, but in that case, the COD will be increased by 3F.

The signals inputted to the input terminals Xln and Ytn are distributed into three parts and transmitted to the input terminals 1, 2, and 3, respectively. This switch is opened and closed at timings S, -1, S, and -2°S-3, and the input is sent to each of the three CCDs 2 and 5.8. On the other hand, the horizontal frequency f of the two methods
, f K to determine the write and read timing of CCDHI H2 by the synchronization control circuit 16.

CCD driving black oscillation circuit 1: fc1+fc2
Output from 3.14 The aforementioned control pulses S-1 to 3,1
1 to 3, and the COD write/read clocks W1 to 3. There is a switching circuit 15 that switches R1 to R3.

The outputs of the three CODs are divided into two, one being returned to the input at the output Banoff -73,6°9, and the other being the one output. These buffers 3 and 6.9 have t-1 to t-1, respectively.
The outputs from the three buffers are added by the adder and q circuit 10, and then the COD clock component is removed. After passing through the L P F 11 K' of Noguru/Kome, output terminal X is output as a converted signal. 1 output to ut, similarly, the signal input to input terminal Y, , is converted, fl
output terminal Y. Output to ut.

Effects of the Invention As described above, according to the present invention, the CCD is used for time compression by changing the transfer lock, and at the same time has the function of storing data by stopping the clock, thereby allowing two different scanning methods to be used. Conversion is now possible.

Specifically, in order to convert the NTSC system to high-definition television formula Vc, it is sufficient to convert only the horizontal frequency, and according to the method of the present invention, it is possible to view NTSC-system images on a high-definition television receiver. can. In this way, format conversion can be performed with a relatively simple circuit configuration, making it convenient to incorporate it into general home television receivers.

[Brief explanation of the drawing]

FIGS. 1, 3, and 5 are waveform diagrams illustrating the entire operation of a scanning line number converter according to an embodiment of the present invention, and FIGS. 2 and 4 are block diagrams thereof. 1.4.7...φ-Person switch, 2,5.8 j...
...CCD, 3,6.9...Nokfufa amplifier, 10...Addition circuit, 11...L
PF, 12... Conversion section, 13.14...
・CCD drive black oscillator, 16・・・CC
D write/read clock switching circuit, 16...
...Synchronization signal control circuit, 17, 19, 21.23...
...R-S flip-flop, p, 18... Monostable multino ζ ibrator, 20, 22.24...
·counter. Name of agent: Patent attorney Toshio Nakao and 1 other person 1st
Figure 3 C (D3 Hp RS w tip
RT-3

Claims (1)

[Claims] Two types of scanning methods having the same vertical frequency but different horizontal frequencies, wherein the horizontal scanning period of the first scanning method is an integral multiple of the horizontal scanning period of the second scanning method. Two types of television signals having a time difference equal to or less than the horizontal period of the first scanning method are received, and the first one. A second and a third charge transfer device are used in parallel, and a signal of the first scanning method is transmitted to the first scan method using a write clock of a first frequency. Second. Sequentially and repeatedly writing to a ninth charge transfer element, stopping the charge transfer element transfer by stopping a transfer block when writing is performed for one horizontal period, and holding the charge transfer element until a horizontal scanning period of a second scanning method that immediately follows; During the horizontal scanning period of the second scanning method, the first. Second
．． The third charge transfer element is repeatedly read out, and when the holding time is smaller than the time difference between the two methods, the first scanning is performed by controlling to read out one more time from one of the charge transfer elements. Second from method
1. A scanning line number converting device that converts the scanning method by filling the scanning lines.