RU2239940C2 - Frequency synthesizer - Google Patents

Abstract

FIELD: radio relay communications technology.

SUBSTANCE: device has circuit for phase auto-adjustment of frequency, generator controlled by voltage, frequency multiplier, band filter, power amplifier, microprocessor, producing signal in form of frequency code which is sent to circuit for phase auto-adjustment of frequency and indication circuit.

EFFECT: higher efficiency.

1 dwg

Description

The invention relates to techniques for radio relay communication and can be used in the equipment of radio relay stations of zonal communication systems as a shaper of stable frequencies defined by a software method.

The well-known “Frequency Synthesizer” (RF patent for the invention No. 2014733, H 03 L 7/22, 1994), which contains a reference oscillator, two tunable oscillators, a divider with a variable division ratio, two phase detectors, two low-pass filters, a non-inverting adder , frequency setting unit, delay element, storage fetch unit.

The disadvantage of this device is a complex circuit using two synchronization circuits.

Also known is the “Fractional Frequency Synthesizer with Phase Synchronization” (RF application for invention No. 98108892, Н 03 L 7/18, 2000), which contains a reference frequency generator, a voltage controlled oscillator, a phase-locked loop, a divider counter and a circuit for control the instantaneous value of the division ratio of the counter-divider.

The disadvantage of this device is the low power level of the output signal, a complex control circuit for the formation of a frequency grid and the lack of indication of operating modes.

It is known to connect an amplifier and a frequency multiplier at the output of a frequency synthesizer to obtain a signal of the required frequency and power (V. Manasevich “Frequency synthesizers. Theory and design.”, Moscow, Svyaz, 1979, p.331-334).

However, this device does not solve, for example, the display task.

It is also known to use frequency synthesizers based on a phase-locked loop PLL frequency lock, frequency capture indicators that respond to signal power (AS USSR No. 732768, N 03 L 7/095, 1980).

The disadvantage of this device is the low power and frequency of the signal.

The closest technical solution is a frequency synthesizer, performed on a phase-locked loop (PLL), containing two dividers with a variable division coefficient, controlled by a microprocessor, to which the command “frequency setting” is received (Shapiro D.N., Pain A.A. “Fundamentals of the theory of frequency synthesis.”, Moscow, Radio and communications, 1981, p.138-139).

The disadvantage of this synthesizer is the low power and frequency of the output signal, as well as the lack of indication of the operating modes of the synthesizer.

The aim of the invention is to obtain at the output of the synthesizer a microwave signal of a given frequency and power, as well as an indication of the operating modes of the synthesizer.

This goal is achieved by introducing into the synthesizer circuit a frequency multiplier with a bandpass filter, a power amplifier and an indication circuit.

The drawing shows the electrical circuit of the synthesizer.

The frequency synthesizer contains a reference oscillator (OG) 1, a microprocessor (MP) 2, a phase-locked loop (PLL), consisting of dividers with a variable division coefficient (DPKD1 and DPKD2) - 3 and 4, respectively, a phase detector (PD) 5 and a filter low frequencies 6, a voltage controlled oscillator (VCO) 7, a frequency multiplier 8, a bandpass filter 9, an indication circuit 10 and a power amplifier 11.

The synthesizer works as follows.

The reference generator provides a stabilized signal to the PLL, which, passing through the first divider with a variable division ratio (DPKD1), is fed to one of the inputs of the phase detector. At the same time, the control signal from the VCO generator passed through the second DPKD2 divider is fed to the second input of the phase detector. In the phase detector, the incoming signals are compared, and if their frequencies are not equal, the phase detector generates a difference (correction) signal, which, passing through the low-pass filter, enters the reactive element of the VCO generator and adjusts its frequency. This happens until the frequencies of the signals arriving at the phase detector are equal. Then the phase detector stops supplying the differential signal for the VCO generator and begins to generate a telemetric signal “frequency capture”, which is fed to the display circuit. The selection of division factors for DPKD1 and DPKD2 is carried out by a microprocessor. The frequency setting signal is fed to the microprocessor from a mechanical switch and allows you to set one of 16 frequency values, the division coefficients of which are embedded in the microprocessor.

The output signal from the VCO generator is fed to a frequency multiplier, which transfers the signal frequency to the microwave range, then to a band-pass filter, which serves to cut off side harmonics, a power amplifier and then to the output of the synthesizer. The power amplifier contains a detector that responds to the level of the output signal of the synthesizer and generates a telemetric signal “power” when the power of the output signal is greater than or equal to the specified one. The telemetric signal “power” is fed to the display circuit.

The display circuit contains three LEDs that inform about the status of the synthesizer. When the telemetry signal “frequency capture” or “power” is received, the corresponding LED lights up. The operation of the LED corresponding to the “accident” telemetric signal is based on the NAND logic, that is, if there are two signals “frequency capture” and “power”, the “emergency” LED does not light. If one or both telemetry signals disappears, the “emergency” LED lights up, signaling insufficient power or a mismatch in the signal frequency required. The lit “capture frequency” and “power” LEDs and the non-lit “accident” LED indicate normal synthesizer operation. The non-lit LEDs “frequency capture” and “power” in combination with the lit “accident” LED indicate that the synthesizer operation parameters do not meet the required ones.

Thus, the introduction of a frequency multiplier with a bandpass filter into the synthesizer circuit allows you to obtain a microwave signal, the introduction of a power amplifier to increase the power level of the output signal, and the display circuit to display the synthesizer operating modes.

Claims (1)

A frequency synthesizer containing a reference oscillator, the output of which is connected to the input of the phase-locked loop (PLL), a voltage-controlled oscillator, a frequency multiplier and a band-pass filter, a power amplifier, a microprocessor that generates a signal in the form of a frequency code, which is fed to the phase diagram auto-tuning the frequency, which also receives a signal from a voltage-controlled generator, while the phase-locked loop generates a correction signal for the generator, controlling voltage indicator, characterized in that an indication circuit is introduced, a power amplifier is connected to the output of the bandpass filter, while the signal “Frequency Capture” or the signal “Alarm” when the frequency of the voltage controlled oscillator is not equal to required, as well as on the display circuit from the output of the power amplifier, a “Power” signal is received at the output signal power corresponding to the rated one, or an “Alarm” signal when the power level is absent or reduced th signal.