JPH04150398A - Color demodulation characteristic measuring device - Google Patents

Abstract

PURPOSE:To measure waveform automatically by allowing a waveform memory to A/D-convert a color difference for a prescribed period and to store the result and allowing an arithmetic processing circuit to read a data stored in the waveform memory and to apply calculation to obtain a color demodulation phase. CONSTITUTION:A test signal generator 11 outputs a TV signal (a). A color television receiver 12 receives a signal (a) from the generator 11 and outputs color difference signals R-Y, G-Y, B-Y as signals (c). A trigger signal generator 14 receives a horizontal synchronizing signal (b) from the TV 12 shown in solid lines or a horizontal synchronizing signal (b) from the test signal generator 11 shown in broken lines to count a scanning number. When the number reaches a prescribed number, a pulse signal (d) is outputted. An arithmetic processing circuit 16 uses a waveform data (e) of the color difference signal stored in the waveform memory 15 to obtain a color demodulation phase theta and the result of calculation (f) is fed to a display device 17. The display device 17 displays the color demodulation phase theta in numeral.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a color demodulation characteristic measuring device for measuring the color demodulation characteristics of a color television receiver, and in particular, to an apparatus for measuring color demodulation characteristics of a color television receiver. The present invention relates to a color demodulation characteristic measuring device that allows color demodulation characteristics to be measured.

(Prior Art) A color demodulation phase characteristic is a characteristic that indicates the performance of a color demodulator of a color television receiver, and this characteristic can be changed by adjusting the W2N of a variable resistor. This is generally referred to as hue adjustment or hue adjustment.
This is called UE) adjustment or TINT) adjustment, and can be adjusted by the user of the color vision receiver. In addition to the above-mentioned variable resistor, which is used by color television receiver users as a device that can adjust the color demodulation phase characteristics, inside the color television receiver, there is also a device that can be adjusted at the color television receiver manufacturing factory. There are semi-fixed resistors, etc., which are used to adjust the variable resistor, etc., and the semi-fixed resistors, etc. are adjusted so that a standard linearity is achieved at the center of the adjustable range of the variable resistor, etc. This adjustment is called sub-hue adjustment or zabuhi: +--(S U B -HU
E) Adjustment or sub-tint (SUB-TIN)
T) It is called adjustment.

FIG. 3 is a block diagram of a color demodulation characteristic measuring device for measuring the color demodulation phase stability adjusted in this manner.

In FIG. 3, the symbol] is a signal generator that generates a signal and a control signal to be supplied to the color television receiver 2 and oscilloscope 3, respectively, which are the object of measurement, and this AST signal generator is , outputs a television signal a of an NTSC chromaticity order color bar image as a test signal from a first output terminal, and outputs a horizontal synchronization signal 1) as a control signal from a second output terminal.

The color television receiver 2 receives the television signal a from the first output terminal of the test signal generator 1 and outputs color difference signals RY and GY.

The B-Y signal is output as the measurement signal from the R-Y signal terminal, the G-Y signal terminal, and the B-Y signal terminal, respectively.

The oscilloscope 3 has a first input terminal connected to one of the RY signal terminal, G-Y signal terminal, and BY signal terminal (for example, the BY signal terminal). Further, a horizontal synchronizing signal from the second output terminal of the test signal generator 1 is supplied to the second input terminal (+- rigger signal input terminal) of the oscilloscope 3. The oscilloscope 3 outputs the horizontal synchronization signal 1) from 1 to rigger signal 1 to
One of the color difference signals is displayed.

Note that the oscilloscope 3 has its vertical axis sensitivity, horizontal axis scanning speed, synchronization level, etc. adjusted to be optimal for observing the measurement signal C.

A measuring method using such a conventional color demodulation characteristic measuring device will be explained with reference to FIGS. 4 and 5.

FIG. 4 is a waveform diagram showing the preview signal a output from the signal generator 1 of FIG. 3, and shows a -horizontal scanning period.

In FIG. 4, the amplitude of the color carrier signal parts 81 to S10 is constant, and the phase is sequentially spaced by 30 degrees from the color subcarrier signal part S1 to the color subcarrier signal part S10 with respect to the burst signal (color synchronization signal) part. The color subcarrier signal part S1 is +
30 degrees, and color subcarrier No. 114 S10 is +300 degrees.

FIG. 5 is a waveform diagram showing one of the 13-Y signals output from the color preview receiver 2 of FIG. 3, and FIG. 5(a) shows the sub-color adjustment. FIG. 5(b) shows the BY signal adjusted to the standard adjustment so that the phase is advanced, and FIG. 5(c) shows the BY signal adjusted so that the phase of the adjustment for the secondary color is delayed. This shows the B-Y signal adjusted to .

In FIGS. 5(a) to 5(b), pulse signal portions P1 to P
10 corresponds to the color carrier wave signal sections 81 to S10, respectively, and when the tips of the pulse signal sections P1 to P10 are connected, a sin curve is drawn. This si
In Figure 5(b), the n curve is shifted to the left in the figure compared to Figure 5<a), and in Figure 5(C) it is shifted to the right in the figure compared to Figure 5(a). .

Such a waveform can be read by the oscilloscope 3.

Pulse signal section P5 displayed on oscilloscope 3
6' The amplitude of P7 is set to L5. T-16゜L 7
, the color demodulation phase θ is determined. This calculation is shown in equation (1).

(1) By performing such calculations, the color demodulation phase θ can be determined, and the color demodulation phase characteristics are adjusted based on this color demodulation phase θ.

However, in measurement using such a color demodulation characteristic measuring device, there is a problem in that the waveform measurement of the oscilloscope 3 involves reading the scale with the naked eye, so there is a large reading error, making it impossible to make accurate measurements. This method has the disadvantage that measurement work is troublesome because calculation work must be performed.

(Problems to be Solved by the Invention) In the conventional color demodulation characteristic measuring device described above, there is a problem that accurate measurement cannot be performed because the scale is read with the naked eye when measuring the waveform of the oscilloscope 3. Because you have to do
There was a problem that the measurement work was troublesome.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a color demodulation characteristic measuring device that can automatically perform waveform measurement and arithmetic processing of the measurement results.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a waveform memory that converts a color difference signal output from a color demodulator of a color television receiver into analog/digital data at a constant cycle and stores the resultant signal, and the waveform memory. an arithmetic processing circuit that reads data stored in the waveform memory and performs calculations to obtain a color demodulation phase; and a display device that displays the calculation results of the calculation processing circuit. It is characterized by having the following.

(Function) According to this configuration, the waveform memory converts the color difference signal from analog to digital at regular intervals and stores it, and the arithmetic processing circuit reads out the data stored in the waveform memory and performs calculations to obtain the color demodulation phase. Therefore, waveform measurement and arithmetic processing of the measurement results can be performed automatically.

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

FIG. 1 is a block diagram showing an embodiment of a color demodulation characteristic measuring device according to the present invention.

In FIG. 1, reference numeral 11 is a test signal generator that generates a D1- signal to be supplied to a color prevision receiver 12 to be measured.
The television signal a of the chromaticity-ordered color bar image of the NTSC system is outputted as the TEST I-signal from the output terminal of the NTSC system. The color preview receiver 12 has a test signal generator 11
The television signal a from the first output terminal of
No., G, -Y (@ No., B-Y signal as measurement signal C,
They are output from the rtY signal terminal, G-Y signal terminal, and B-Y signal terminal, respectively. - On the other hand, the trigger signal generator 14 inputs the horizontal synchronizing signal b from the color television receiver 12 shown by the solid line or the horizontal synchronizing signal b from the test signal generator 11 shown by the broken line, and receives the horizontal synchronizing signal b from the test signal generator 11 shown by the broken line. Count the scanning line number from . When the count value reaches a predetermined measurement scanning line number, a pulse signal is output as a storage start signal d. When the waveform memory 15 receives a first input terminal of the color difference signal, for example, a BY signal, and a second input terminal receives a storage start signal from the trigger signal generator 14, the waveform memory 15 stores the color difference signal. is continuously converted from analog to digital at a constant sampling period, and when a storage start signal is supplied, storage into the memory is started, and the waveform of the color difference signal is digitally stored. In this case, the data stored in the waveform memory 5 includes waveforms such as those observed with the conventional apparatus in the states shown in FIGS. 5(a) to 5(C) as digital numerical values for each sampling period.

The arithmetic processing circuit 16 calculates the color demodulation phase θ by performing the calculation described later using the stored data e of the waveform of the color difference signal stored in the waveform memory 5, and supplies the calculation result f to the display device 17. The display device 17 displays the color demodulation phase θ using, for example, numbers.

1. The operation of the arithmetic processing circuit 16 will be explained using the explanatory diagram of FIG.

The arithmetic processing circuit 16 selects pulse signal portions P1 to P10 from among the waveform data of the color difference signals stored in the waveform memory 15.
Extract the data (see Figure 5) as stored data e,
The array data are respectively D[1] to D[10]. Next, the following calculations are performed using these array data D[11 to D[10].

D[1]...-+-D [5] -1-D [8]・
・・1−D[101... (2) D[11]= (D[5] −Z)1)[11・
・t ]) [4] 11) [7]・ +D [1
0]... (4) D [12] = -(D [6] -Z)... (
5) By performing equations (2) to (5), array data D [11] and D [12] are obtained.

330 degree and 360 degree data are interpolated using such array data. Figure 4 shows these array data D[Mon~D[1
2] is plotted, and the phase angle (color demodulation phase) θ
It becomes a sine wave with one period whose frequency corresponds to the horizontal scanning frequency of the color television receiver 12. Here, the phase angle θ is equal to the phase angle obtained by adding a certain value to the color demodulation phase of the color television receiver 12, and B
- When the Y signal is measured, the added value is 160 degrees.

Next, the arithmetic processing circuit 4 processes the array data D[month~D[1
2] is used to perform the Fourier transform shown below.

R[kl 1 [kl ・ (7) By performing equations 6) and (7) in this way, the time domain array data I) [1] to .]) [12] can be converted into the frequency domain is converted to subprime array data of R
Array data of [11 to R[12] and imaginary part ■ [1] to
Sequence data of I [12] is obtained. Real part data R[2] of frequency domain complex number data after Fourier transform
and imaginary part data {circle around (2)} are data of one period component in the array data D[1] to D[12] before Fourier transform, which corresponds to the horizontal scanning frequency of the color television receiver 2. Furthermore, the arithmetic processing circuit 4 processes the real part data R[2] and the imaginary part data ■[ after Fourier transformation.
2] to perform the calculations shown below.

By performing such equation (8), the performance processing circuit 4
calculates the phase angle (color demodulation phase) θ.

According to such an embodiment, since waveform measurement and arithmetic processing of the measurement results can be automatically performed by the waveform memory 15 and the arithmetic processing circuit 16, the labor of the operator can be reduced, and the color demodulation phase characteristics can be precisely measured. can be measured.

[Effects of the Invention] As described above, according to the present invention, waveform measurement and arithmetic processing of the measurement results can be performed automatically, so the labor of the operator can be reduced, and color demodulation phase characteristics can be accurately determined. Can be measured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a color demodulation characteristic measuring device according to the present invention, FIG. 2 is an explanatory diagram illustrating the calculation of the arithmetic processing circuit in FIG. 1, and FIG. 3 is a conventional color demodulation characteristic FIG. 4 is a waveform diagram showing the television signals output by the D1 to signal generators in FIG. 3, and FIG. FIG. 3 is a waveform diagram showing a Y signal. 11...Design signal generator, 12...Color television receiver, 14...I-
trigger signal generator, 15... waveform memory 16... arithmetic processing circuit, 17... display device. LIJ

Claims (1)

[Scope of Claims] A waveform memory that converts a color difference signal output from a color demodulator of a color television receiver from analog to digital at a constant cycle and stores it; a trigger signal generator that instructs the waveform memory to start storing; A color demodulation characteristic measuring device comprising: an arithmetic processing circuit that reads data stored in the waveform memory and performs a calculation to obtain a color demodulation phase; and a display device that displays the calculation results of the arithmetic processing circuit.