SU860344A1 - Device for correcting signal distortion in facsimile picture recording - Google Patents

Description

one

The invention relates to a facsimile technique and can be used to compensate for image distortion introduced by a recorder's electromechanical converter.

A device for correcting signal distortion during facsimile image recording is known, which comprises a delay unit and an adder 1.

However, the known structure has an insufficient degree of correction.

The aim of the invention is to exaggerate the degree of correction.

In order to achieve the goal of the facsimile signal distortion correction signal, the image containing the delay unit and the adder, the first AND-NAND unit sequentially inputted, the front-end impregnator, the expander of the additional corrective impulses, the second AND-NOT element, the output of which is connected to the first the adder input, as well as the successively connected rear edge driver and the white signal conditioner, the output of which is connected to the second input of the adder, the output being about

The NAND element is connected via a serially connected delay block and the input black signal generator is connected to the third input of the adder, and the second input of the black signal signal generator} is connected to the second output of the additional correction pulse generator, the input of which is connected to the fourth input of the adder, and the second output of the pulse shaper front edge connected to the first input of the first element

10 AND-NOT, the second input of which is intended for supplying the input corrected signal, and the input and the second output of the rear FSD pulse generator are connected respectively to the output of the delay unit and to the second input of the second N-element.

The drawing shows a structural {wiring diagram of the proposed device.

The device for correcting the distortion of signals during facsimile image recording contains

20 delay unit 1, adder 2, first AND-NOT 3 element, 4 front-edge impulse generator, shaper 5 additional correction pulses, second AND-NO 6 element, back-edge shaper 7, white shaper 8, and black shaper 9. The device works as follows. The first input of the first element IS-HE 3 receives a rectangular signal of duration t, in which white corresponds to 1, and black to O. The second input of this element is given a formed front accelerating pulse of duration t forms l 4. At the output of the first element IS-NOT 3, an impulse is formed whose duration is greater than or equal to the duration of the forward accelerating impulse. The pulse from the output of the imaging unit 4 is fed to the inverting input of the adder 2, as well as to the imaging unit 5, which contains a delay circuit of the forward accelerating pulse for the duration tg of the correction pulse. A correction pulse arrives at the first input of the second NAND element 6. A pulse from the output of the first NAND element 3 in parallel arrives at a delay unit 1 with a delay time tj, from which a signal is fed to one of the inputs of the imaging unit 9 and to the imaging unit 7 with a duration tj. A signal whose duration is equal to the sum of the 11th accelerating and correcting pulses (t + tj) is sent to the other input of the imaging unit 9. At the output of the imaging unit 9, a black signal is generated, which corresponds to 1 in. time t -t to, - t 2 The last signal is also fed to the inverting input of adder 2. Shaper 7 also has an output of the signal delayed by a time equal to t + t. + t. This signal is inverted in the driver 8, from where it is fed to the non-inverting input of the adder 2. The rear accelerating pulse is fed to the second input of the second element AND-HE 6, the output of which produces both correction and rear accelerating pulses. The last signal arrives at the non-inverting input of adder 2. As a result of the four signals at the input, an alternating signal is formed, in which the level of accelerating, correcting pulses, black and white, can be changed separately as specified. The duration of the nepBioro accelerating pulse is chosen equal to half the period of the specified maximum frequency of the played video signal O. The voltage level of this pulse is selected from the condition of providing sufficient current in the converter to move the feed part from the upper position above the paper to the paper in the specified time interval TG-t. Typically, the amount of force with which a writing element attached to the moving part is pressed against the 44 paper after the setting process is 1.53 times less (for high-speed record Ers) the force required to move the moving part in time f. If the voltage level acting during the forward accelerating pulse is maintained, this results in a breakthrough of the paper and damage to the writing element. Following the accelerating impulse, there is a correction impulse of opposite polarity compared to the front accelerating impulse. Its purpose is to absorb the inertia of the movement of the moving part in the shortest time, reducing the magnitude of the first, and hence subsequent emissions of the transient response. When the pulse sign changes, the direction of the force acting on the moving part also changes, so the correction takes place in the shortest time that can be (0.1-0.2) t. In this case, during the action of the correction impulse, the mobile part does not have time to start moving in the opposite direction, but only stops. After the completion of the correction pulse, a black signal is transmitted, the level of which is higher, this level can be adjustable, it is selected based on the level of normal recording of a uniform field. The device allows maximum use of the speed of the electromechanical converter, the time of movement from the upper position of the food element to the paper. At the same time, it can be equal to the minimum duration of the reproduced video signal pulse. This entails distortion in the form of a thinning of the reproduced image elements, especially noticeable, thin lines. In order to compensate for this distortion, a block 1 of the delay duration of the black signal, which can be equal to 0.5, is introduced. After the end of the black signal, the driver Y generates a rear accelerating pulse of reverse polarity compared to the front accelerating pulse. Its time may be only 0.5 t, since in the most critical case, reproducing thin white strokes of minimal duration against a black background is enough for the writing element to slightly tear away from the paper and not go all the distance to the top position above the paper. The white level should be the minimum necessary to maintain the writing element at a sufficient distance above the paper. This level is selected 1.2-2 times less than the black level. The technical and economic effect from the application of the proposed device for correcting signal distortion during facsimile image recording is achieved due to the increased degree of correction and the possibility of separate adjustment of pulse levels, as well as black and white levels.

Claims (1)

Invention Formula The device for correcting the distortions of signals in the facsimile image, containing a block-delay and an adder, is confusing to the fact that, in order to increase the degree of KoppeKibra, the first connected AND-NOT element, the front-edge driver, the driver of additional correction pulses were introduced, the second IS input, the output of which is connected to the first input of the adder, as well as series-connected rear edge driver and white signal former, the output of which is connected to volts rum input of the adder, the output The first NAND element is connected via a serially connected delay block and the black signal generator is connected to the third input of the adder, and the second input of the black signal generator is connected to the second output of the additional correction pulse generator, the input of which is connected to the fourth input of the adder of the front is connected to the first input of the first NAND element, the second input of which is intended for supplying an input corrected signal, and the input and the second output form The pulse gate of the trailing edge is connected respectively to the output of the delay unit and to the second input of the second NAND element. Sources of information taken into account in the examination 1. US patent N 4030121, cl. H 04 N 5/14 1977 (prototype).