CN205142181U

CN205142181U - Low stray broadband 10~20GHz phase -locked loop device

Info

Publication number: CN205142181U
Application number: CN201521004667.5U
Authority: CN
Inventors: 方涌; 尹红波; 王洪林
Original assignee: Yangzhou Haike Electronic Technology Co Ltd
Current assignee: Yangzhou Haike Electronic Technology Co Ltd
Priority date: 2015-12-07
Filing date: 2015-12-07
Publication date: 2016-04-06
Anticipated expiration: 2025-12-07

Abstract

The utility model relates to a low stray broadband 10~20GHz phase -locked loop device, a serial communication port, reference amplifier, phase -locked loop, voltage controlled oscillator, coupler, buffer and frequency divider including connecting gradually still include loop filter, CPLD and TCXO, wherein: loop filter respectively with the phase -locked loop with voltage controlled oscillator is connected, the frequency divider with the phase -locked loop is connected, CPLD respectively with the phase -locked loop with TCXO is connected. The utility model provides a low stray broadband 10~20GHz phase -locked loop device, circuit design is simple, does not need complicated filter circuit, and sub - harmonic is stray low, and output spectral purity is high, and digital spurious interference is low, and SMT technology is adopted in the circuit equipment, and simple process can satisfy practical application's needs well.

Description

A kind of low spurious broadband 10 ~ 20GHz phase-locked loop apparatus

Technical field

The utility model belongs to phase-locked loop apparatus technical field, is specifically related to a kind of low spurious broadband 10 ~ 20GHz phase-locked loop apparatus.

Background technology

Microwave Frequency Source is the core component of various electronic system, and microlock source circuit is the common circuit in Microwave Frequency Source.The phase-locked loop circuit structured flowchart of prior art as shown in Figure 1.If microwave current phase locked source main circuit is made up of phase-locked loop (PLL) chip, VCO, loop filter.Phase-locked loop (PLL) chip is made up of digital frequency divider and phase discriminator, and its internal register needs to be loaded by serial or parallel bus, and digital noise just passes through serial or parallel bus parasitic to VCO output, produces spuious; The operating frequency of phase-locked loop (PLL) chip only has 8GHz, for the microlock source circuit of frequency higher than 8GHz, need to add frequency dividing circuit at the input of phase-locked loop (PLL) chip, and the isolation of frequency divider to output frequency is limited, it is spuious that the sub-harmonic wave that such frequency division produces will export the sub-harmonic wave of formation at VCO.Want to meet spuious index, just need more complicated switched filter circuit, add the complexity of device.

Utility model content

For above-mentioned problems of the prior art, the purpose of this utility model is to provide a kind of low spurious broadband 10 ~ 20GHz phase-locked loop apparatus avoiding occurring above-mentioned technological deficiency.

In order to realize above-mentioned utility model object, the technical solution adopted in the utility model is as follows:

A kind of low spurious broadband 10 ~ 20GHz phase-locked loop apparatus, comprise the reference amplifier, phase-locked loop, voltage controlled oscillator, coupler, isolated amplifier and the frequency divider that connect successively, also comprise loop filter, CPLD and TCXO, wherein: described loop filter is connected with described voltage controlled oscillator with described phase-locked loop respectively; Described frequency divider is connected with described phase-locked loop; Described CPLD is connected with described TCXO with described phase-locked loop respectively.

Further, described isolated amplifier comprises the first attenuator, amplifier and the second attenuator that connect successively.

Further, described CPLD is EPM570T100I5.

Further, described TCXO is connected with magnetic bead and tantalum electric capacity.

Further, the model of described tantalum electric capacity is TAJA106K016RNJ.

Low spurious broadband 10 ~ 20GHz phase-locked loop apparatus that the utility model provides, circuit design is simple, do not need complex filter circuit, sub-harmonic wave is spuious low, output spectrum purity is high, and digital parasitic disturbances is low, and Circuit assembly adopts SMT technique, technique is simple, can meet the needs of practical application well.

Accompanying drawing explanation

Fig. 1 is the phase-locked loop circuit structured flowchart of prior art;

Fig. 2 is the circuit structure block diagram of phase-locked loop apparatus of the present utility model;

Fig. 3 is the circuit theory diagrams of isolated amplifier of the present utility model;

Fig. 4 is the circuit diagram of control unit of the present utility model.

Embodiment

In order to make the purpose of this utility model, technical scheme and advantage clearly understand, below in conjunction with the drawings and specific embodiments, the utility model is described further.Should be appreciated that specific embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.

As shown in Figure 2, a kind of low spurious broadband 10 ~ 20GHz phase-locked loop apparatus, comprise the reference amplifier, phase-locked loop (PLL), voltage controlled oscillator (VCO), coupler, isolated amplifier and the frequency divider that connect successively, also comprise loop filter, CPLD (CPLD) and TCXO (temperature compensating crystal oscillator), wherein: described loop filter is connected with described voltage controlled oscillator with described phase-locked loop respectively; Described frequency divider is connected with described phase-locked loop; Described CPLD is connected with described TCXO with described phase-locked loop respectively.CPLD and TCXO forms the control unit of phase-locked loop apparatus.

VCO is the operating frequency of 10 ~ 20GHz, spuious in order to reduce sub-harmonic wave, selects the degree of coupling of 15dB.This degree of coupling can realize easily on microstrip circuit, and printed circuit board technique is easily processed, and cost is low, and provides 15dB to isolate the reverse leakage of frequency divider to the signal that VCO holds.Microstrip coupled line has the first port, the second port, the 3rd port and the 4th port four ports, and wherein, the first port meets VCO and exports, and the 3rd port is coupling termination isolated amplifier, and the second port is straight-through output, and the 4th port needs to connect 50 ohm load.In current techniques, be used as 50 ohm load of 10 ~ 20GHz with common resistance, voltage standing wave ratio is bad, has impact to coupling performance.The attenuator that the utility model have employed 20dB carrys out alternative 50 ohm load, ensure that coupler performance.

As shown in Figure 3, described isolated amplifier comprises the first attenuator ATT1, the amplifier A1 and the second attenuator ATT2 that connect successively, for the VCO signal that amplifying coupler coupling comes, and isolates the reverse leakage signal of frequency divider.The ingenious forward that make use of amplifier of isolated amplifier amplifies, reverse attenuation characteristic.First attenuator ATT1 and the second attenuator ATT2 is 3dB decay, and the gain of amplifier A1 is 21dB, and reverse isolation is 40dB.The reverse leakage signal of isolated amplifier to frequency divider has the isolation of 46dB.Frequency divider itself has 40dB to the isolation of reverse leakage signal, adds the isolation 15dB of coupler circuit, and the reverse leakage signal isolation of whole phase-locked loop apparatus to frequency divider is greater than 100dB, and switched filter circuit that can be complicated realizes high spuious index.

As shown in Figure 4, CPLD and TCXO forms the control unit of phase-locked loop apparatus, control unit, according to external interface order, loads phase-locked loop (PLL) chip internal register, VCO is locked in the frequency of requirement by phase-locked loop (PLL) chip.The CPLD of control unit adopts programming device EPM570T100I5, needs could work with clock.The digital noise that the shake of digital dock produces produces interference by the interface line of phase-locked loop (PLL) chip to phase-locked loop (PLL) chip, finally can be parasitic on the near-end of the output spectrum of VCO.The utility model preferably adopts the clock of TCXO (temperature compensating crystal oscillator) as EPM570T100I5 of 20MHz, and this TCXO has low clock jitter and low spurious.Power supply is isolated TCXO (temperature compensating crystal oscillator) and EPM570T100I5 power supply with magnetic bead and tantalum electric capacity, effectively prevent signal cross-talk.TCXO is connected with magnetic bead and tantalum electric capacity, the model of tantalum electric capacity is TAJA106K016RNJ.

The above embodiment only have expressed execution mode of the present utility model, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the utility model the scope of the claims.It should be pointed out that for the person of ordinary skill of the art, without departing from the concept of the premise utility, can also make some distortion and improvement, these all belong to protection range of the present utility model.Therefore, the protection range of the utility model patent should be as the criterion with claims.

Claims

1. low spurious broadband 10 ~ 20GHz phase-locked loop apparatus, it is characterized in that, comprise the reference amplifier, phase-locked loop, voltage controlled oscillator, coupler, isolated amplifier and the frequency divider that connect successively, also comprise loop filter, CPLD and TCXO, wherein: described loop filter is connected with described voltage controlled oscillator with described phase-locked loop respectively; Described frequency divider is connected with described phase-locked loop; Described CPLD is connected with described TCXO with described phase-locked loop respectively.

2. low spurious broadband according to claim 1 10 ~ 20GHz phase-locked loop apparatus, is characterized in that, described isolated amplifier comprises the first attenuator, amplifier and the second attenuator that connect successively.

3. low spurious broadband according to claim 1 10 ~ 20GHz phase-locked loop apparatus, is characterized in that, described CPLD is EPM570T100I5.

4. low spurious broadband according to claim 1 10 ~ 20GHz phase-locked loop apparatus, is characterized in that, described TCXO is connected with magnetic bead and tantalum electric capacity.

5. low spurious broadband according to claim 4 10 ~ 20GHz phase-locked loop apparatus, is characterized in that, the model of described tantalum electric capacity is TAJA106K016RNJ.