SU640416A1 - Arrangement for phase-wise automatic tuning of frequency - Google Patents

Description

one

The invention relates to radio engineering and can be used in various devices to extract a harmonic signal from a mixture of additive noise and a signal.

A phase locked loop (PLL) device containing serially connected quadrature input to video converter, made in the form of serially connected synchronous detector, limiting amplifier, intermitter, other input of which is connected to the input of synchronous detector and quadrature phase detector, and threshold limiter are known voltage changes, as well as series-connected low-pass filter and controlled oscillator, the output of which is connected with other inputs of synchronous and quadrature phase detectors of the quadrature converter of the input signal to the video frequency 1.

However, the known device, when operating on a non-manipulated signal, has an output voltage phase uncertainty, which means that the controlled generator is in synchronism with both the phase difference between the sinusoidal input signal and the controlled generator signal, equal to 0 °, and the phase difference, equal to 180 °.

The aim of the invention is to eliminate the non-determination of the phase of the controlled oscillator.

To do this, in a PLL device containing a series-connected quadrature input-to-frequency converter, made in the form of a series-connected synchronous detector, a limiting amplifier, a multiplier, the other input of which is connected to the input of a Sihroine detector and a quadrature phase detector, and a threshold limiter as well as series-connected low-pass filter and controlled oscillator, the output of which is connected to other inputs of the synchronous and quadrature phase detectors of a quadrature input to video frequency converter; between the threshold speed limiter output and the lowpass filter input are connected series-connected smoothing filter, DC amplifier, and adder, to the outputs of the quadrature phase detector and the square limiter amplifier of the input signal an additional circuit is connected to the video frequency, the output of which is connected to another input of the adder.

The drawing shows a structural electrical circuit of the proposed device.

The PLL device contains serially connected quadrature converter 1 input signal into video frequency, made in the form of serially connected synchronous detector 2, amplifier-limiter 3, non multiplier 4, another input connected to the input of synchronous detector 2 and quadrature phase detector 5, threshold limiter 6 c KopocTii. changing the voltage from the bottom, as well as sequentially connected low-pass filter (FMF) 7 and controlled oscillator 8, the output of which is connected to other inputs of synchronous and q drafts phase detectors 2 and 5. Between the output of threshold limiter 6 and the input of the low-pass filter 7 there are connected in series a smoothing filter 9, a direct current amplifier (UFD) 10 and an adder 11, to the outputs of the quadrature phase detector 5 and the amplifier-limiter 3 an additional multiplier 12 is connected whose output is connected to another input of the adder 11.

The device works as follows.

In the beating, voltages shifted by 90 ° appear at the outputs of the synchronous detector 2 and quadrature phase detector 5, and at the output of the quadrature phase detector 5 with phase jumps per l due to switching on the input 4 at its input 4. At the output of the additional multiplier 12 the voltage in shape is close to sinusoidal and shifted by / 2 with respect to the voltage at the output of synchronous detector 2. Symmetric voltage at the output of quadrature phase detector 5, having passed through threshold limiter 6, becomes asymmetric As a result, the output of the smoothing filter 9 is a constant component, which, after amplifying the DCF 10, creates the effect of adjusting the controlled oscillator 8. As the beat frequency decreases, the voltage at the output of the additional amplifier 12 differs more and more from a sinusoidal waveform. how the conventional PLL begins to act. The beat direction of one sign increases the frequency offset, and this “no-second period” is heard, and the sound of the beat of another sign decreases the offset.

and THIS “semi-periody rast hivae1s. As a result, a constant voltage component and at the output of an additional multiplier 12 occur, which leads in a wake counting to phase-locking in a loop consisting of low-pass filter 7, a controlled oscillator 8, a quadrature phase detector 5, an additional multiplier 12, an adder 11 with the participation of the multiplier 4. After the phase has been captured, the threshold limiter 6, the squelting filter 9 and the FPT 10 provide for the production of corrective matching, which reduces the phase error in steady state.

Thus, the proposed device retains all the advantages of the known device and, in addition, eliminates in it the uncertainty of the phase of the output sial.

Claims (1)

1. USSR author's certificate L 595842, cl. P OZV 3/04, 1974.  f f   7