CN204362031U - The fast frequency-hopped local vibration source of L-band - Google Patents

Abstract

The utility model is an L-band fast frequency hopping local oscillator, which solves the problem that the frequency hopping time of the traditional phase-locked loop circuit is usually tens of microseconds and the frequency hopping time is long. The output of the reference crystal oscillator (1) is connected to the phase detector (2), the output of the phase detector is connected to the loop filter (3), the output of the loop filter is connected to the voltage-controlled oscillator (4), and the voltage-controlled oscillation One output of the voltage-controlled oscillator is connected to the phase detector, the other output of the voltage-controlled oscillator is connected to the filter (6) through the frequency division circuit (5), and the control circuit 7 is connected to the phase detector.

Description

L-band fast frequency hopping local oscillator source

Technical field:

The utility model relates to a frequency hopping frequency source.

Background technique:

The frequency hopping frequency source is usually implemented by a phase-locked loop circuit. The phase-locked loop circuit has the characteristics of low cost and good spectrum quality. However, the frequency hopping time of the traditional phase-locked loop circuit is usually tens of microseconds, and the frequency hopping time is long, which often cannot meet the requirements. Application of frequency-agile systems.

Utility model content:

The purpose of the utility model is to provide an L-band fast frequency hopping local oscillator source with fast frequency hopping speed, good spectrum quality and low cost.

The utility model is achieved in that:

The L-band fast frequency hopping local oscillator source, the output of the reference crystal oscillator 1 is connected to the phase detector 2, the output of the phase detector 2 is connected to the loop filter 3, and the output of the loop filter 3 is connected to the voltage controlled oscillator 4, The output of the reference crystal oscillator 1 is connected to the phase detector 2, the output of the phase detector 2 is connected to the loop filter 3, the output of the loop filter 3 is connected to the voltage-controlled oscillator 4, and one output of the voltage-controlled oscillator is connected to the detector The phase detector is connected, the control circuit 7 is connected to the phase detector, and the other output of the voltage-controlled oscillator is connected to the filter 6 through the frequency division circuit 5 .

Reference crystal oscillator 1 adopts 80MHz temperature-compensated crystal oscillator to provide a reference reference frequency for the whole circuit. Phase detector 2 adopts ADF4159 fractional-N frequency synthesizer. The reference signal and voltage-controlled oscillator signal are phase-identified and output control signals here. The filter controls the response of the phase-locked loop negative feedback circuit through a reasonable zero-pole design. The voltage-controlled oscillator 4 uses HMC588LC4B to realize the X-band 8000-9600MHz signal output. The frequency division circuit 5 divides the output signal of the voltage-controlled oscillator. To the L band, realize the frequency output of 1000-1200MHz, the filter 6 will suppress the stray after the frequency division of the voltage controlled oscillator, and ensure that the stray signal is less than 60dBc, and the control circuit 7 realizes the configuration and skipping of the phase detector 2 frequency control.

L-band fast frequency hopping local oscillator source through the reasonable planning of output frequency, combined with the use of phase-locked loop circuit, frequency division circuit and filter, L-band fast frequency hopping local oscillator source realizes the fast frequency hopping of L-band, through Using a signal analyzer to test its frequency hopping time, the frequency hopping time from 1000MHz to 1200MHz is less than 1.5us, the phase noise of the local oscillator is better than 100dBc/Hz10KHz, 103dBc/Hz100KHz, and the clutter suppression is greater than 75dBc. Its frequency hopping time, phase noise and other indicators are superior to similar phase-locked local oscillators, and has the advantages of fast frequency hopping speed, good spectrum quality and low cost.

Description of drawings:

Figure 1 is a schematic diagram of the phase-locked loop circuit.

Figure 2 is a block diagram of the L-band fast frequency hopping local oscillator source.

Figure 3 is a schematic diagram of the L-band fast frequency hopping local oscillator source.

Detailed ways:

The L-band fast frequency hopping local oscillator source is composed of a reference crystal oscillator, a phase detector, a loop filter, a voltage-controlled oscillator, a frequency division circuit, a filter, and a control circuit.

The L-band fast frequency hopping local oscillator source, the output of the reference crystal oscillator 1 is connected to the phase detector 2, the output of the phase detector 2 is connected to the loop filter 3, and the output of the loop filter 3 is connected to the voltage controlled oscillator 4, The output of the reference crystal oscillator 1 is connected to the phase detector 2, the output of the phase detector 2 is connected to the loop filter 3, the output of the loop filter 3 is connected to the voltage-controlled oscillator 4, and one output of the voltage-controlled oscillator is connected to the detector The phase detector is connected, the control circuit 7 is connected to the phase detector, and the other output of the voltage-controlled oscillator is connected to the filter 6 through the frequency division circuit 5 .

Reference crystal oscillator 1 adopts 80MHz temperature-compensated crystal oscillator to provide a reference reference frequency for the whole circuit. Phase detector 2 adopts ADF4159 fractional-N frequency synthesizer. The reference signal and voltage-controlled oscillator signal are phase-identified and output control signals here. The filter controls the response of the phase-locked loop negative feedback circuit through a reasonable zero-pole design. The voltage-controlled oscillator 4 uses HMC588LC4B to realize the X-band 8000-9600MHz signal output. The frequency division circuit 5 divides the output signal of the voltage-controlled oscillator. To the L band, realize the frequency output of 1000-1200MHz, the filter 6 will suppress the stray after the frequency division of the voltage controlled oscillator, and ensure that the stray signal is less than 60dBc, and the control circuit 7 realizes the configuration and skipping of the phase detector 2 frequency control.

The reference crystal oscillator Y1 is TFASAN-80.00MHZ to provide the frequency reference for the local oscillator source circuit. Capacitors C29, C30 and EC4 are crystal oscillator power filter capacitors to reduce the interference of low frequency signals to the crystal oscillator. The phase detector U2 is ADF4159, where the signals of the reference crystal oscillator and the voltage-controlled oscillator are phase-detected and control signals are output. EC1, C19, C20, C10, C11, C4 and C5 are phase detector power supply filter capacitors, R9, R10, R 11, R12 and R13 are phase detector control signal protection resistors, C15, C16, C17 and C18 are phase detector The filter controls the line filter capacitor to reduce the interference of the radio frequency signal to the phase detector. The voltage-controlled oscillator U3 is HMC588LC4B, and the output signal range is 8000-9600MHz. EC3, C24 and C25 are the power supply filter capacitors of the voltage-controlled oscillator to reduce the interference of low-frequency signals to the voltage-controlled oscillator. R15, R16 and R17 form a π-type attenuation network, which attenuates the amplitude of the voltage-controlled oscillator output signal, and at the same time matches the impedance of the output signal. R18, R20 and R21 form a T-shaped power distribution network, which converts the voltage-controlled oscillator signal The power is divided into two channels, one is output to the frequency divider, and the other is output to the RF signal pin of the phase detector. The operational amplifier U1 is AD8065ARZ, which forms an active loop filter with C3, R1, R2, C2, R8 and C12, and the output signal of the charge pump of the phase detector passes through the active loop filter to the output of the voltage-controlled oscillator The frequency is controlled, C6 and C7 are the power filter capacitors of the op amp, and R7 and R6 provide the bias voltage for the positive terminal of the op amp. The frequency divider U4 is HMC363S8GE. The output signal of the T-shaped power distribution network passes through the resistors R22, R25 and R26 to form a π-type attenuation network, and then it is divided by the frequency divider by eight and then output. The device FZ1 is a LFCN-1200+ low-pass filter, which suppresses the spurious signals generated by the frequency divider.

The L-band fast frequency hopping local oscillator has passed the signal analyzer test of xx company. The working frequency is 1000-1200MHz, the working bandwidth is 200MHz, and the frequency hopping time is less than 1.5us. In the -1200MHz frequency range, the phase noise of the L-band fast frequency hopping local oscillator source is better than 100dBc/Hz10KHz, 103dBc/Hz100KHz, and the clutter suppression is greater than 75dBc.

The list of components is shown in Table 1.

Table 1 L-band fast frequency hopping local oscillator source device list:

Claims (2)

1. L-band fast frequency hopping local oscillator source, the output of the reference crystal oscillator (1) is connected to the phase detector (2), the output of the phase detector is connected to the loop filter (3), and the output of the loop filter is connected to the voltage The control oscillator (4) is connected, and one output of the voltage control oscillator is connected to the phase detector. It is characterized in that the other output of the voltage control oscillator is connected to the filter (6) through the frequency division circuit (5), and the control circuit ( 7) Connect with the phase detector. 2. The L-band fast frequency hopping local oscillator source according to claim 1, characterized in that the reference crystal oscillator (1) adopts an 80MHz temperature-compensated crystal oscillator to provide a reference reference frequency for the entire circuit, and the phase detector (2) adopts ADF4159 fractional N The frequency division frequency synthesizer, the reference signal and the voltage-controlled oscillator signal are phase-identified and the control signal is output here. The loop filter (3) controls the response of the negative feedback circuit of the phase-locked loop through the design of the zero-pole, and the voltage-controlled oscillator (4) HMC588LC4B is used to realize the X-band 8000-9600MHz signal output. The frequency division circuit (5) divides the output signal of the voltage-controlled oscillator to the L-band to achieve a frequency output of 1000-1200MHz. The filter (6) divides the voltage-controlled oscillation The stray after the frequency division of the detector is suppressed to ensure that the stray signal is less than 60dBc, and the control circuit (7) realizes the configuration and frequency hopping control of the phase detector.