SU1287260A1 - Sawtooth current generator - Google Patents

Abstract

The invention relates to a pulse technique and can be used in scanning devices of transmitting TV cameras, in particular with a pyroelectric vidicon. The purpose of the invention is to increase the linearity of the deviation of the electron beam during the reverse sweep stroke by introducing into the generator a second key 3, a diode 7, a second current generator 5, a controlled voltage source 11 and a second power bus 12. The generator also contains the first switch 1, the input bus 2, the current generator 4, the capacitor 6, the power amplifier 8, the deflection of the kitsu coil 9, the first power supply bus 10. The proposed sawtooth generator can be used in devices where high linearity of the reverse sweep stroke is required to create a uniform distribution of electrons over the target. 1 pe. (L

Description

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The invention relates to a pulse technique and can be used in scanning devices of transmitting television cameras, in particular with a pyroelectric vidicon.

The purpose of the invention is to increase the linearity of the deflection of the electron beam during the reverse sweep.

Functional diagram of the device. shown in the drawing.

The device contains a first switch, an input bus 2, a second switch 3, the first and second generators 4, 5 current, capacitor 6, diode 7, power amplifier 8, deflection coil 9, first power bus 10, controlled source 15, second bus 12 nutrition

The input bus 2 through the first key 1 is connected to the first input of the second key 3, the second input of which is connected to the output of the second generator 5, and the output to the cathode of the diode 7, the anode of which is connected to the output of the first generator 4, the control inputs of the first and second generators 4 , 5p through a capacitor 6 - with a bus and through an amplifier 8 and a deflecting coil 9 also with a common bus. The first bus GO is connected to the input of the first generator 4 and the return terminal of the controlled source I, the input of which is connected to the second bus 12, and the output - with the input of the second generator a 5.

The first key 1 when there is no sync pulse on the input bus 2 is the input of the key 3 to the common bus. The second key 3 can be performed, for example, on a pp transistor, whose base is connected to a common bling, the collector is the key output, and the emitter is connected to the first and second inputs. The first and second generators 4, 5 of the current are identical in the same circuits, but on transistors of different polarity: the emitter through a resistor is connected to the input of the current generator — the collector is its output; the voltage on the base is set by the resistor 1, which is: Between the current generator input and the common bus, an additional control signal is fed through a resistor to the base or emitter of the transistor.

On the first bus. About power - positive voltage, on the second bus.

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12 - negative. Controlled source 11 at its output creates a negative voltage, varying in proportion to the positive voltage at its control input, and can be performed according to one of the known schemes of controlled voltage regulators.

The sawtooth generator operates as follows.

Between the clock pulses fed to the input bus 2 (forward sweep), the current of the second generator 5 is short-circuited to the common bus with key 1, the key 3 is locked, and the capacitor 6 is charged by the current of the generator 4, the feedback voltage applied to the control bus The generator 4 input allows the linearity of the sawtooth voltage on the capacitor 6 to be adjusted (by selecting the value of the corresponding resistor in the generator 4), making it convex or concave and thus providing the best linearity of the deviation of the elecron beam in the tube. Transmitting tube.

When the clock pulse appears, the first switch 1 is disconnected and the discharge of the capacitor 6 starts through the diode 7 and the second switch 3 of the current, equal to the difference of the absolute values of the currents of the second and the first generators 5 4. . The feedback from the capacitor 6 to the control input of the generator 5 makes it possible to adjust the linearity of the sweep during reverse.

To vary the sweep amplitude, the voltage on the first power bus 10 is adjusted. In this case, the generator current 4 and, consequently, the voltage range across the capacitor 6 to the current range in the deflecting coil 9. The voltage at the output of the controlled source I1 varies proportionally (in absolute value of the voltage on the first bus 10, 11th of this, the discharge current also varies, and the time of the linear portion of the reverse sweep does not change when its amplitude is adjusted.

This sawtooth generator can be used in measuring television systems, including those based on a pyroelectric vidicon, where high linearity of the reverse sweep is required.

to create a uniform distribution of electrons in the target.

Claims (1)

Invention Formula A sawtooth current generator containing the first switch, the first current generator, the input of which is connected to the first power bus, and the output to the first capacitor plate and through the power amplifier connected in series and the deflecting coil to the common bus and the second capacitor plate, connected to the input bus, characterized in that, in order to increase the linearity of the deflection of the electron beam during 872604 reverse sweep, a second switch, a diode, a second current generator, a controlled voltage source, and a second power bus, 5 moreover, the output of the first key is connected to the first input of the second key, the second input of which is connected to the output of the second current generator, and the output to the cathode of the diode, the anode of which 10 is connected to the input of the power amplifier and the control inputs of the first and second current generators, and the input and control input of the controlled voltage source are connected J5, respectively, with the second and first power supplies, and the output with the input of the current generator.