SU374768A1 - COLORED TELEVISION CAMERA - Google Patents

Description

one

The invention relates to transmitters of color television systems.

Color television transmitting chambers are known that contain a transmitting tube, on which a stencil consisting of opaque strips, preliminary and intermediate amplifiers are designed.

However, the black level in such cameras is unstable.

The purpose of the invention is to obtain accurate ratios of color separations and to reduce the instability of the black level.

This is achieved by introducing a differential amplifier, a match block, a delay line, an amplitude limiter, an amplitude modulator and a subtractor.

The block diagram of the camera described in the drawing.

Transmitting chamber contains a grid of opaque vertical strips, transmitting television tube 2, preamplifier 3, differentiating amplifier 4, coincidence circuit 5, delay line 6, coincidence circuit 7, delay line 8, amplitude limiter 9, amplitude modulator 10, line 11 delay integrating amplifier 12 subtracting

the device 13, the delay line 14 and the intermediate amplifier 15.

A video signal containing information about the black signal level, obtained when the electron beam reads the raster sections corresponding to the location of the opaque bars of the lattice, from the output of the transmitting tube through the preamplifier goes to a differentiating amplifier, allowing you to more clearly determine the moments of the raster sections corresponding to the electron beam the location of the opaque bars of the lattice. The output of the differentiating amplifier signal is received

to one input of the coincidence circuit 5 and through the delay line 6, the delay time of which corresponds to the width of the opaque grid strip, to its second input. The impulse signals from the output of the coping circuit 7 with a duration corresponding to the width of the opaque bars of the lattice are received at one input of the coincidence circuit 7 and through the delay line 8, the delay time of which corresponds to the distance between the opaque strips

lattice - at its other entrance. From the output of the coincidence circuit 7, a control signal corresponding to the moments of the passage of the electron beam through the raster sections that carry information about the magnitude of the video signal from the (Non-transparent lattice strips through the amplitude limiter is fed to the control input of the amplitude-impulse modulator to the signal input of which video signal from the preamplifier output through delay line 11, which takes into account the time delay of the control signal.

From the output of the amplitude-pulse modulator, the pulse signals carrying information about the signal size from the opaque bars of the array go through an integrating amplifier to a subtractor, the second input of which receives the video signal from the output of the preamplifier via delay line 14. The latter takes into account the delay time in the device for generating a signal about the level of a black signal in a video signal. From the output of the subtractor, a video signal containing information about the true level of the black signal with respect to the damping pulse arrives at the intermediate amplifier.

Subject invention

A color television transmitting chamber containing a transmitting tube, on the photosensitive surface of which a stencil is designed, consisting of opaque strips perpendicular to the horizontal scanning direction, and preliminary and intermediate amplifiers,

that, in order to obtain accurate ratios of color separation signals and eliminate black level instability, a differentiating amplifier is connected to the preamplifier output, the output of which is connected to one of the inputs of the coincidence unit directly and to the other through the second delay line, and the output of the coincidence unit is connected to one of the inputs of the second coincidence unit directly, and with others through the second delay line, while the second coincidence unit is connected via amplitude limiter to amplitude impu snym modulator, a signal input coupled via a further delay line output with the preamplifier, and the output pulse amplitude modulator is connected via an integrating amplifier to the subtracter, the second input thereof via a second additional line

5 delays are connected to the preamplifier output, and the output of the subtractor is connected to the input of the intermediate amplifier.