SU1224971A2 - Tracking filter - Google Patents

Abstract

The invention relates to radio engineering. In relation to the main. auth. No. 978322 decreases the tuning time to the first harmonic of the input signal when the false harmonic is tuned to the second harmonic of the input signal. The device contains input and output pulse drivers 1 and 3, a tunable band-pass filter (PPF) 2, a phase detector 4, a low-pass filter (FCP) 5, a shunt switch 7 and a time discriminator 6 consisting of a counting trigger 8, three matching elements (ES) 9, 11, 12, static trigger 10 and element OR 13. At the time of arrival of the second harmonic pulse from the output pulse shaper 3 at ES 12, it is triggered and the signal from its input goes to the control of the shunt key 7, zeroed the signal at the output of the FN H 5, which leads to a rearrangement of W1F 2 to the lower boundary of the working range of the following filter. After the termination of the signal from the output of the ES 12, the voltage at the output of the LPF 5 will begin to increase from a constant time of the LPF 5 from zero to a voltage corresponding to the setting of the PDF 2 to the first harmonic of the input signal frequency. The pulse duration from the output of the ES 12 does not affect the effect of tuning since the zeroing of the signal at the output of the low-pass filter 5 occurs on the leading edge of the signal from the output of the ES 12. 2 Il. - i (L

Description

The invention relates to radio engineering and measurement technology and can be used in radio engineering and measuring devices for various purposes.

The purpose of the invention is to reduce the time of tuning to the first harmonic of the input signal with a false adjustment to the second harmonic of the input signal.

Figure 1 shows the structural electrical circuit of the following filter; Fig. 2 shows voltage diagrams for the following operation of the following filter.

The following filter contains an input pulse shaper 1, a tunable tunable filter 2, an output pulse shaper 3, a phase detector 4, a low-pass filter 5, a time discriminator 6, a shunt switch 75, a counting trigger 8, the first element 9 coincides static trigger 0, the second element 11 matches, the third element 12 matches, the element OR 13.

The following filter works as follows.

The input shaper 1 generates rectangular input frequency pulses that arrive at a band-tunable filter 2 with a controlled resonant frequency, at the input of the phase detector 4, at the input of the counting trigger 8 and at the Echo of the static trigger 10 (Fig. 2a),

From the output former 3, the pulses go to the second input of the phase detector 4, to the second inputs of the first, second and third elements 9, 1 and 12, respectively, of coincidence (Fig. 52a). The control input of the band-tunable filter 2 from filter 5 is energized by the projection of the output signal phase from the input signal selected by the phase detector 4 and adjusts the band-tunable filter 2 to the input frequency (Fig. 25k). From one of the outputs of the counting trigger 8 - (FIG. 2B), pulses with a duration equal to the period of the input frequency are fed to the input of the first coincidence element 9, from the other output of the counting trigger 8 pulses with a duration equal to the period of the input frequency are fed to the input of the second matching element 11

249712

() The other inputs of the first and second elements 9 and 11 receive pulses from the output formative cell 3 pulses (Fig.-2a) .. At the time of S the stroke of the first pulse from the output shaper 3, the first element 9 is triggered and the signal from its output goes through the element OR 13 to the input of the static trigger 10. So

W as a static trigger 10 is triggered on the trailing edge of the pulse, i.e. in-moment of loss of pulse from the output of the output shaper 3, then, the third element 12 is not cpa6aTbfBaeT

15 due to the absence of a pulse at its second input (FIG. 2 p). With the arrival of the second pulse from the output of the input shaper 1, arriving at the second input of a static trigger

20 W, the static trigger 10 is switched to the initial state. At the moment of arrival of the second pulse from the output shaper 3, the second element 11 coincides, and

25, the signal from its output goes through the OR element 13 also to the first input of the static trigger 10. The static trigger W triggers at the moment of the pulse disappearing from the output of the output shaper 3, and the third element 12 does not trigger due to the absence of an impulse at its second input.

When adjusting the tracking filter to the second harmonic of the input frequency

35 signal that may occur at. a sharp change in the input signal, at the moment of switching on, in case of short-term power failure, from the output phase E and 3 during the period

 The input frequency receives two pulses (Fig, 2 g). At the moment of arrival of the second harmonic pulse from the output shaper 3 to the third element 12, the third element 12 triggers (Fig. 2e), and the signal from its output goes to the control input of the shunt key 7, which zeroed the signal at the output of the filter 5 low frequencies (Fig. 2g), which leads to a transition of the tunable tunable filter 2 to the lower limit of the operating range of the next filter. After the termination of the effect of the signal from the output of the third element 12, the voltage on

 the output of the low pass filter 5 begins to increase (Fig.) with a constant time of the low pass filter 5 from zero to a voltage corresponding to 3 2

tune tunable filter 2 to the first harmonic frequency of the input signal.

Since the zeroing of the signal at the output of the low-pass filter 5 occurs on the leading edge of the signal from the output of the third element 12, the duration of the pulse from the output of the third element 12 does not affect the effect of the rearrangement.

Claims (1)

Invention Formula Next filter by bus. St. ff 978322, characterized in that, in order to reduce the tuning time to the first harmonic of the input signal with a false adjustment to the second harmonic of the input signal, Order 1963/57 Circulation 816 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 71 four the time discriminator contains a peg match element and a countable connected in series. a trigger, a second match element, an OR element whose other input is connected to the output of the first match element, a static trigger and a third match element whose output is the output of a temporary discriminator, the other output of the counting trigger is connected to the input of the first match element, the other inputs of the first, second and third match elements are the first input of the temporary discriminator, the input of the counting trigger and the other input of the static trigger are the second input of the temporary discriminator.