SU455248A1 - Television photoelectric meter for measuring chromaticity co-ordinates - Google Patents

Description

one

The invention relates to the field of color television, namely television measurements.

A television photoelectric chrominance co-ordinator for serial action is known, which contains a luminous flux analyzer connected by one of the outputs through an amplifier, the feedback circuit of which includes a resistive voltage divider and an alternating voltage converter in the analog-code constant of the converter, the comparison device , the input of which is connected to the output of the amplifier, the first output of the comparator device is connected via a pulse shaper to the first input of the coincidence circuit, the second input The second output is connected through the delay circuit to the amplifier output, the second output is connected to the counter input, the outputs of which are connected to the inputs of the decoder connected to the outputs of the keys, the outputs of which are connected to a resistive voltage divider, connected to the output of the coincidence circuit, arithmetic unit and indicator at its output.

In such meters, the possibility of increasing the accuracy of measuring chromaticity coordinates is not fully used due to the large relative errors in converting analog values to digital form, which occurs at small values of these values relative to the maximum value of the conversion range. The aim of the invention is to increase

accuracy of measurement of chromaticity coordinates.

In the proposed meter, this is achieved by the fact that the outputs of the luminous flux analyzer, the analog-code converter and the decoder are connected via an additional decoder to the input of the arithmetic unit.

The drawing shows the block diagram of the proposed meter. The meter contains a luminous flux analyzer 1, an amplifier 2, an alternating voltage-to-constant voltage converter 3, an analog-code converter 4, a decoder 5, an arithmetic unit 6, an indicator 7, a device 8 for comparing signals DC at, counter 9

for counting the number of pulses taken from the output of the comparison device 8, the decoder 10, the keys 11-13 controlling the resistive divider 14 of the feedback voltage connected between the input and the output

the amplifier 2, the pulse driver 15, the coincidence circuit 16, the delay circuit 17 and the light filter changer 18. The feedback voltage divider 14 consists of resistors 19-22. Arithmetic unit

6 consists of counters 23-25.

Measuring the chromaticity coordinates works as follows.

To reduce the effect of discreteness on the result of calculating the chromaticity coordinates, it is necessary to set the optimal gain factor of amplifier 2 for each of the three consecutive signals X, Y, Z coming from the analyzer 1 of the light flux.

In the process of setting the optimum gain factor, the signal from the output of the amplifier 2 is fed to the comparison device 8, where the signal magnitude is compared with the value of 1/31. If the magnitude of the signal is greater than t / fl, then a pulse is output from the output of the comparator to the counter 9, which through the decipher 10 sets the required resistance of the resistive divider 14 to the feedback voltage. The process of setting the optimum gain factor continues until the signal size becomes less. In this case, the signal from the output of the comparison device 8 through the pulse shaper 15 and the coincidence circuit 16 is fed to the changer 18 light filters, giving the command to set the next light filter. For example, when a light filter is installed for signal X, the optimum gain of amplifier 2 is set, and depending on the state of inputs of decipher 5 associated with the outputs of analyzer 1 of the light flux, the encoded signal can be written to counter 23 for coded signal X and counter 25 for coded amount. Similarly, when a light filter is installed for a signal Y, the encoded signal can be recorded only in counter 24 for the coded signal Y and in counter 25. When the light filter is set for signal Z, the encoded signal can be recorded only in counter 25.

The state of the outputs of the decoder 10 determines the supply of the coded signal to the input

corresponding discharge counters of the arithmetic unit 6. In turn, the output states of the decoder 10 are determined by the optimal gain factor of the amplifier 2.

Thus, it is possible to reduce the magnitude of the conversion errors of the analog value to the digital code, which occur when the measured values of X, Y, Z are small, and thereby increase the accuracy of determining the chromaticity coordinates.

Subject invention

Television photoelectric chrominance co-ordinator

flow, connected by one of the outputs through an amplifier, in the feedback circuit of which a resistive voltage divider is connected, and an alternating voltage converter in the constant to the input of the converter

the code, the comparator device, the input of which is connected to the output of the amplifier, the first output of the comparator device is connected through the pulse shaper to the first input of the coincidence circuit, the second input of which through the circuit

the delay is connected to the output of the amplifier, the second output is connected to the counter input, the outputs of which are connected to the inputs of the decoder connected to the outputs of the keys, the outputs of which are connected to a resistive voltage divider, an optical filter changer connected to the output of the coincidence circuit, an arithmetic unit and an indicator its output, characterized in that, in order to improve the accuracy of measuring chromaticity coordinates, the outputs of the luminous flux analyzer, the analog-code converter and the decoder are connected via An additional decoder to the input of the arithmetic unit.

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