SU871256A1 - Method of analog signal processing - Google Patents

Description

(54) METHOD FOR PROCESSING ANALOG SIGNALS

one

The invention relates to the field of analog signal processing using storage silicon cathode ray tubes and can be used in devices for the selection of moving objects, in automated systems for monitoring and rejecting products, to expand operational methods of diagnostics in medicine, to detect extraneous inclusions in liquid medicines, in high-precision holographic measuring devices, etc.

A known method of processing analog signals, consisting in recording and subtracting signals directly on the target of a storage electron tube (ZELT), in which the first recording of signals on a ZELT target, corresponding to the distribution of luminance levels over the observed static field, is carried out in the "fast electrons" mode with the secondary electron emission of the dielectric of the target is greater than 1, then a second recording is made in the mode of "slow electrons with the secondary electron emission coefficient of the dielectric

is less than 1, and the reading of the difference information is carried out by an electron beam with electron energy, at which the coefficient of secondary electron emission of the target dielectric is less than 1.

The disadvantage of it is the low accuracy of the selection of signals of moving objects.

The closest to the proposed method is the processing of analog signals using a memory cathode tube with a crosshair target and an alignment grid by preparing the target to record scanning it at a constant bias on the leveling grid, exceeding on, spun on the conductive substrate of the target, electronically beam 5 of a constant density arc with electron energy, at which the coefficient of secondary emission of the dielectric of the target is greater than 1, recording information in the form of a potential relief by scanning its electron A constant-density beam with an energy at which the secondary emission coefficient is less than 1 and which is carried out by applying a voltage to the bias voltage of the conducting substrate of the recorded signal and subtracting the current information from the recorded 2.

This method also has the disadvantage noted above.

The aim of the invention is to improve the accuracy of the selection of signals of moving objects against a fixed background.

This goal is achieved by the fact that in the method of processing analog signals using a storage electron tube with a silicon target and an alignment grid by preparing the target for recording by scanning it with constant mixing on an alignment grid exceeding the voltage on the conducting substrate of the target, a constant electron beam density with electron energy at which the coefficient of secondary emission of the target dielectric is greater than 1, recording information in the form of a potential relief by scanning it with an electron beam n a density with an energy at which the secondary emission coefficient is less than 1 and which is carried out by applying a voltage to the bias voltage of the conductive substrate of the recorded signal, and subtracting the current information from the recorded, by applying to the conductive substrate, subtracting by supply voltage to the conductive substrate of the target — smaller than the bias voltage when recording, by the amount of the black information level of the processed information, shifting the current information signal to negative values by the magnitude of the said black level, superimposing the current information signal on the bias voltage of the conducting substrate of the target and scanning the target with a constant-density electron beam at the same speed and along the same trajectories as in the recording, while the bias voltage on the equalizing the grid is kept constant and equal in magnitude to the bias voltage in preparation for recording, and the difference signal is removed in the equalizing grid circuit.

FIG. 1 shows a scheme allowing to implement the method; in fig. 2 - a more detailed scheme of the target.

The device contains (see Fig. D and 2) the electron-beam tube 1, the bias voltage block 2, the control voltage block 3, the horizontal block 4 and the frame scan 5, the synchronizer 6, the switch 7, the shift block 8, the amplifier 9, the switch 10, the substrate 11, the target 12, the alignment grid 13, the beam 14 and the cathode 15.

The method can be carried out, for example, as follows.

When preparing the target for a new record, the ZELT 1 leveling grid from the bias voltage block 2 serves voltage, for example (+) 500 V, and the bias voltage 3 is applied to the target substrate ZELT 1 from the voltage controlled block 3, less than offset bias voltage leveling grid, for example (-f) 495 V, using line 4 and frame 5 sweep units produce lower case and frame sweep voltages, which are fed to the deflecting plates of the ZELT 1, while the ZELT modulator 1 from the block synchronizer 6 serves pulses that, on duration equal direct

0 in the course of the line scan, and thus scan the target with an electron beam of constant density. The secondary electron emission coefficient of the target dielectric in this case is greater than 1, and the elements of the dielectric mosaic of the target ZELT 1

5 acquire a positive charge. The potential of the dielectric mosaic elements of the ZELT 1 target will increase until the potential of the ZELT 1 leveling grid is reached; this process is happening

very quickly, and after completing the scanning of the target, all the elements of its dielectric mosaic will have a potential of (4-) 5 V relative to the conductive substrate of the target. The secondary electrons are collected by the self-aligning grid of the ZELT 1.

5 When writing, the equalization grid of the ZELT 1, as before, is maintained at a potential of (-f) 500V, and the bias voltage of the (-f) 15 V is applied to the conducting substrate of the ZELT 1 target through R 50 kΩ from the controlled voltage block 3 The block 3 is controlled by the signals of the synchronizer 6. The input video signal, which is the recorded information and changing within 5 V from the black level to the white level, is fed through

5 a switch 7, controlled by the signals of the synchronizer 6, onto the conductive substrate of the target ZELT 1; wherein the voltage on the wire substrate of the target ZELT 1 varies from (-f) 15 V to (+) 20 V, respectively, for levels of white and black,

0 and the gray scale is represented by an appropriate voltage distribution between (+) 15 V and (-) 20 V. The target is scanned with an electron beam of constant density, the secondary emission coefficient of the dielectric of the ZELT 1 target is less than 1, and the electron beam of the ZELT 1 brings the potential of the dielectric mosaic target to a zero potential of the ZELT cathode 1. As a result of scanning the target, a potential

0 relief accurately reproducing the sum signal on the conductive substrate of the target.

The subtraction of the current information from the recorded one is performed as follows: a bias voltage is applied to the conducting substrate of the ZELT 1 from the block of controlled voltages 3, which is less than the bias voltage when writing by the amount of black information being processed, (+) 10 V through resistance R 50 kOhm shifts the video signal level of the current information into the region of negative values by the amount of the black level of the processed information using the level shift block 8 and imposes a signal with the shifted level through the switch 7 for example The displacement of the conductive target substrate, the target is scanned with a constant density electron beam, the speed and scanning paths during recording and subtraction are the same, the current information signal level is shifted simultaneously with the start of the subtractive beam scanned, the bias voltage on the alignment grid ZELT 1 is kept constant - (+) 500 V.

If the current signal and the recorded ZELT 1 target are the same, which corresponds to the case of stationary objects, then due to the level shift of the current value of the signal to the area of negative values by the value of the black level, which is precisely determined for the particular ZELT operation mode and is equal to the dynamic Range of the control characteristic of the ZELT and supplying the signal with a shifted level to the circuit of the conducting substrate of the target ZELT 1 synchronously with the movement of the subtractive beam along the lines of the record, additionally modulate the potential accumulated in the target This is such that the instantaneous value of the potential of the dielectric mosaic elements of the target is equal to the lock-up potential on all scan lines, and no electron of the subtractive beam can hit the conductive substrate of the target, which essentially means suppression of signals from stationary objects, and the difference signal in the leveling grid circuit does not occur, since all electrons of the constant-density subtractive beam are reflected from the target and are absorbed by the leveling grid of the self-electric TLT1.

In the case of moving objects, the current signal differs from that recorded at the target, the instantaneous potential of the elements of the dielectric mosaic of the target will not be equal to the potential of locking the target on all scan lines, when the current signal is shifted into the circuit of the conducting target substrate synchronously with the movement of the subtractive beam. the area of negative values for the black level of the processed information, and during the passage of the subtractive beam over the elements of the dielectric mosaic of the target, on which the white level is recorded, and the instantaneous value of the current signal is equal to the black level, a part of the electrons of the subtractive beam reaches the conducting substrate of the target, the number of reflected electrons absorbed by the equalizing grid decreases, and a positive polarity pulse appears in the chain of the equalizing grid, indicating that the object is mobile. This pulse is applied to the amplifier of the difference signal 9, and through the switch 10, controlled by synchronizer 6 and allowing the signal to pass only after subtraction in the circuit of further processing.

The use of the proposed method of processing analog signals in comparison with the known methods provides for the subtraction of current information from the recorded with high geometrical accuracy, which makes it possible to isolate with high accuracy the signals of moving objects against a stationary background and makes it possible to create highly accurate analog signal processing devices using the difference inter-frame signal in time frames.

Claims (2)

1. US Patent No. 3993926, cl. 315-10, published. 1976. 2. US patent number 4004182, cl. 315-12, pub. 1977 (prototype).