SU429497A1 - DEVICE FOR PHASE AUTO CONSTRUCTION OF FREQUENCY - Google Patents

Description

one

The invention relates to radio engineering and can be used in receivers of FM and FM signals, in frequency synthesizers.

There is a device containing in-phase and quadrature channels, a tunable oscillator, whose frequency control input is connected via a low-pass filter to the output of an in-phase channel phase detector, a la, and the output of a quadrature channel phase detector is connected to a key control input.

However, the known device has a significant transition time and insufficient width of the capture band.

The aim of the invention is to reduce the time of the transition process and the expansion of the capture band.

For this, the electronic switch in the device is provided with an additional output connected via an inverter to the additional input of the low-pass filter integrating unit.

The drawing shows a functional block diagram of the device.

The device for phase locked loop contains in-phase 1 and quadrature 2 channels, phase detector 3 in-phase 4 and quadrature channels, low-pass filter 5, adjustable oscillator 6, phase shifter 90 ° 7, key 8, electronic

the switch 9, the integrating unit 10, the differentiating unit 11, the inverter 12.

The output of the device can serve as the output of the adjustable generator 6.

The device works as follows. When a signal is applied to the device input, beats appear at the outputs of phase detectors 3 and 4. The beat voltage at the output of the phase detector 4 of quadrature channel 2 at

the phase shifter assist 7 is phase shifted relative to the voltage at the output of the phase detector 3 of the common mode channel by 90 °. In the half-period of beats, when the output of the phase detector 4 of the quadrature channel voltage is negative, which corresponds to an increase in detuning, the key 8 produces a pulse applied to the input of the switch 9, which connects the input of the inverter 12 to the output of the differentiating block 11, which leads to reduce the frequency mismatch. With a positive half-wave, the beating voltage at the output of the control device is not generated, and the switch connects the output

differentiating unit 11 directly to the second input of the integrating unit 10.

The introduction of an additional inverter 12 into the low-pass filter structure 5 reduces the transient time and extends the capture band to a value close to the hold band.

Subject invention

A device for phase a1vt Podod, frequency moduli containing in-phase and quadrature channels and a tunable oscillator, the frequency control input of which is connected through a low-pass filter made in the form of integrating and differentiating blocks connected to the phase detector of the in-phase phase detector, and the output of the quadrature phase detector of the channel to the control input of the key, inclusive between the differentiating and integrating low-pass filter units, characterized in that, in order to reduce the transition time the process and the extension of the capture band, in it the electronic switch is equipped with an additional output connected via an inverter with an additional input of the integrating low-pass filter unit.