SU115926A1 - The method of synchronization of the transmitting and receiving devices of color television with sequential transmission of colors across the fields - Google Patents

Description

In the known methods of synchronization of a transmitting and receiving device in a color television system with sequential color transmission, a complex synchronization signal is sent over the air, containing frame, line and phasing pulses. When using a clock signal of a known form, devices that provide system in phase and installed at the receiving end are very complex.

The described method of synchronization and synchronization pulses you / delépi, based on a rational choice of durations entered into the sync mixture of signals, their rational arrangement and on the use of a certain time delay when the pulses are differentiated on the receiver side, makes it possible to simplify the color television receiver synchronization unit.

The sync signals (sync mix signals) include horizontal sync pulses, vertical sync signals of about 40% of the horizontal sync period, and color phasing pulses of about 16% of the horizontal sync pulses entered in each the third field and the available distances of one horizontal period, from the leading edge of the personnel clock pulse.

To ensure synchronization sustainability, the auxiliary signal-satellite, with a duration of 8% of the row pulse period, is placed in each field at a distance of 10% of the row length from the trailing edge of the frame pulse when the frame pulse is separated by differentiation. Duration # 115926-2 -

The consistency of the horizontal sync pulses is reduced to 8%. FIG. 1-3 shows a complex sync waveform for color television and methods for extracting clock pulses; in fig. 4 is a circuit for separating frame pulses and voltage forms at various points thereof: FIG. 5 shows a method for isolating a phasing pulse. The complex sync signal for the various fields shown in FIG. 1a, 2a, za, za, allows the use of a differentiation method and a time delay for the selection of frame pulses. The process of extracting a frame clock pulse by differentiating for even red fields is shown in FIG. 16 for odd red fields — in FIG. 26, for even green and blue fields — in FIG. 36 and for odd green and blue fields — in FIG. 36. The dashed line shows the level of limitation. The resulting two pulses of identical shape, having the same amplitude, are used to synchronize the receiver's frame sweeps.

The amplitude of the video signal before it is selected at the output of the video amplifier in positive polarity significantly exceeds the solution characteristics of the first restrictive lamp. In the anode of this lamp, a complex sync signal (without a video signal) has a negative polarity, and a differentiated personnel impulse is positive. From the cathode of the second half of the triode (Fig. 4) a frame clock signal is taken, which will be identical in form and amplitude for all fields. It also shows the waveform at points 1, 2, 3, 4, 5 and 6 of the circuit.

The selection of frame pulses for odd red fields using a delay line is shown in FIG. 2e ,, 2g and in FIG. 2e shows a complex synchronous signal (FIG. 2a), delayed 40% by a line, and FIG. 2g is the result of the addition of the signals indicated in FIG. 2a and 2e. The signal 2g after differentiation is shown in FIG. 2i.

The selection of frame pulses for odd green and blue fields is shown in FIG. Zv Zg, Zd. FIG. Sv shows the signal shown in FIG. Over, delayed by a line for 40% of the duration of the period of lower-case pulses (I); in fig. 3g is the result of the addition of Za and Zv, and in FIG. Zd - signal Zg after differentiation.

The selection of frame pulses for even red fields is shown in FIG. 1e, 1i, 1zh. FIG. 1e shows a signal 1a delayed by a line at 40% of the length of the period of horizontal pulses (I) in FIG. 1 and the result of the addition of signals 1a and 1e; in fig. 1g - signal 1and after differentiation.

The selection of frame pulses for even green and blue fields is shown in FIG. Sv, Zg, Zd: na fig. Sv shows the signal For, shifted by 40% I, in FIG. Zr is the result of the addition of signals Za and Sv, and in FIG. Zd - signal Zg after differentiation. The dotted line shows the level of restriction everywhere.

The selection of a phasing pulse by a line for even red fields is shown in FIG. 1v, 1g, 1d. FIG. 1c shows a 16% shifted I complex sync signal; in FIG. 1d is the result of the addition of signals 1a and 1b, and in FIG. 1e is the 1g signal after differentiation. FIG. 2c, 2d, 2d shows the selection of a dosing pulse by a line for odd red fields. FIG. 2c shows a signal 2a shifted by 16%; in FIG. 2d is the result of the addition of signals 2a and 2b, and in fig. 2d - 2g signal after differentiation.

The general principle of pulse extraction using a time delay and subsequent differentiation is shown in FIG. 5a, 56, 5b, 5g: in fig. 5a shows an oscillogram of a synchro blend of signals of various durations; FIG. 56 - subtraction of signals, due to the time delay using the equivalent of a long line, closed at the end. Here, signal A is shifted by its duration and, subtracted from the main signal, forms a double voltage drop, formed by the trailing edge of the initial pulse and the front of it shifted in front of it. The waveform 5c shows the pulses after differentiation, and 5 g shows the same pulses after limiting.

The described waveform of synchro mixes, in addition to the indicated methods of extracting the necessary signals, allows other methods of extraction designed to use them under special conditions, such as:

1. Isolation of personnel clock pulses only through differentiation as applied to receivers operating within the same ring of the AC network, where the separation of color phasing pulses is not necessary.

2. Isolation of personnel clock pulses by differentiating, and pulsing the color of the pulses by temporarily shifting the extracted pulse, received on the equivalent of a long line, followed by differentiation (for the case of receiver operation from an AC network not connected to the network supplying the transmitting device) .

Subject invention

Claims (3)

1. A method of synchronizing a transmitting and receiving device of color television with sequential color transmission across fields, using a complex synchronization signal containing a narrow frame synchronizing and equalizing pulses of a black and white television system, characterized in that, in order to provide phasing, every third The field is introduced with a narrow 16% pulse away from the leading edge of the frame sync pulse at a distance of one row period. 2. Acceptance of the method according to claim 1, characterized in that, in order to increase the efficiency of separating human impulses from a complex syncthiscation signal when they are differentiated, the duration of horizontal impulses is reduced to 8%, and the duration of personnel ones is increased to 40% of the horizontal period clock pulses. 3. Acceptance of the method according to paragraphs. 1 and 2, characterized in that, in order to increase the efficiency of the selection of a personnel pulse, or a color phasing pulse, carried out by differentiating the sync pulse pulses, additionally, using the equivalent of a long line closed at the end, produce a temporary shift of the output pulse, which makes equal to its duration so that the falling edge of the pulse being generated, coinciding with the leading edge of the reflected pulse that is in antiphase, creates for the differentiating circuit a double voltage drop. No. 11592 & Jl U -L, -U one TH 4i H