SU746566A1 - Pneumatic adaptive filter - Google Patents

Description

, The invention relates to instrumentation, namely to analog pneumatic smoothing devices, i Self-adjusting non-linear filters are known, containing a backwash block with a signaling device for limiting values at the input. And and 2. A disadvantage of the known devices is the low filtration accuracy of the useful signals with changes in the level of interference. In the proposed adaptive filter, a reverse prediction unit and a limit value detector, the output of which is connected to the control input of the reverse anticipation unit, are installed with an inductor, capacitance, and integrator, with one of the limit value inputs from the integrator output, and its output through the throttle and capacitance is connected to the input of the integrator. The drawing shows an adaptive filter diagram. The filter contains a block 1 reverse prediction. The limiter 2 limit values, consisting of comparison elements J-4, choke 5, capacitance 6 and integrator 7. The input of the backward block 1 is connected to the input channel Pd of the filter and the first input of the signaling device 2. The second input of the warning device is connected to the output channel Pftbiji. filter and the output of block 1 reverse. The control input of unit 1 is connected to the output of the detector and through a choke 5 and capacitance 6 to the input of the integrator 7, and the output of the integrator 1 is connected to the third input of the alarm: the mountain. Chambers supporting the integrator 7 and the detector 2 are respectively supplied with the first Pd and the second P bearing pressures. Adaptive filter works as follows. With a constant input signal, while the level of interference is in the dead zone of the detector 2, the output of the detector is O (atmosphere), which is fed to the control input of the reverse precursor and sets a large time constant in it. As a result, block 1 filters out interference, which is determined by means of a detector as the modulus of the difference between the input and output of the back-preceding block Rb -P8b1L b

When a useful signal is given in jumps, the jPe misalignment jPe of Rva-) 1 (exceeding the insensitivity zone of the signaling device), a signal 1 (supply pressure) is generated at the output of the signaling device, which, entering the control input of the reverse anticipation unit, abruptly sets a small constant As a result, the useful signal jumps to the output of block 1, the deviation value {Рц Bbijtl will again correspond to the width of the dead zone of the alarm device, the output of which will take the value O and in the reverse block will set a large time constant, as a result of which block 1 will again filter out the interference. In the case of a change in the useful signal at high speed at which it is not filtered by the de-blocking mechanism, due to the large time constant, the signal at the output of the detector switches with a frequency equal to the frequency of the coiled noise, in block 1 with the same frequency, the value of its temporal will switch and as a result the useful signal at the output of the filter will be processed almost without distortion (the higher the oscillation frequency interference, the less distorted the useful signal at the output).

With the help of self-tuning, consisting of droplets 5, capacitance b and integrator 7, it is automatically detected; |) ae% yo bo of the dead zone of the signal level of the signal.

If the width of the dead zone is less than the level of interference, then the output of the alarm device will generate a signal 1 (supply pressure), switching with a frequency equal to twice the frequency of interference. This signal, smoothed by choke 5 and capacity b, after comparison with the first reference pressure P, will be integrated by link 7 until the zone width becomes equal (or rather slightly less) the level of interference.

If the width of the dead zone is greater than the noise level, then the output of the detector is always O (atmosphere), therefore, the pressure in tank 6 is zero. In this case, the output signal is integ; . Rotor 7 under the action of the reference pressure Pgjj will decrease until the deadband of the alarm level of the interference level becomes equal.

When the level of interference (noise) changes, the self-tuning circuit works in a similar way.

Thus, due to the intermittent change in the constant time

5 backward block

rapid changes in the useful signal, the latter is filtered with almost no distortion. In addition to TSEGO, due to the use of a self-tuning circuit filter

0 has the ability to adapt to the level of interference,

This makes it possible to significantly improve the filtration accuracy, which leads to an increase in the quality of control of technological parameters under the effect of interference in the chemical, petrochemical and other sectors of the industry.

Claims (2)

1. USSR Author's Certificate for Application No. 2330871/24, cl. G 05 B 13/00, 03/04/76. 2. USSR author's certificate No. 210232, cl. G 05 13/00, 1969 (prototype).