CN206135883U - Low phase noise interpolation phase -locked loop circuit - Google Patents

Abstract

The utility model discloses a low phase noise interpolation phase -locked loop circuit, it includes reference circuit, skew source circuit and interpolation phase locked loop, the reference signal that reference circuit provided is divided into two the tunnel, supplies all the way the skew source circuit to produce required shifted signal, and another way is the reference signal who offers interpolation phase locked loop, and interpolation phase locked loop is with the low frequency signals that produces after feedback signal and the mixing of skew source signal as whole closed -loop circuit's the feedback looks frequency of reflecting. The phase noise of the mode of feeding back mirror looks frequency, improvement output frequence signal is reduced through the skew source mixing of making an uproar better mutually. Overcome traditional closed loop feedback system and be subject to making an uproar mutually of phase discriminator and concern floorFom+10log (Fpd) 20log (FvcoFpd), under the condition of guaranteeing the same frequency dividing ratio, can realize higher frequency resolution simultaneously. It must increase the frequency dividing ratio to overcome traditional phase -locked loop when the high -frequency, nevertheless reduced the shortcoming of frequency resolution simultaneously.

Description

Low phase noise interpolation phase-locked loop circuit

Technical field

This utility model is related to the communications field, particularly a kind of Low phase noise interpolation phase-locked loop circuit.

Background technology

Phaselocked loop realizes output using the frequency and phase place of the reference signal control loop internal oscillation signal of outside input Signal frequency is generally used for Closed loop track circuit to frequency input signal from motion tracking.Be radio transmitting in make frequency compared with For a kind of stable method, mainly there is VCO (voltage controlled oscillator) and PLL IC (phase-locked loop intergrated circuit), voltage controlled oscillator is given Go out a signal, a part makees phase bit comparison with the local oscillation signal produced by PLL IC by frequency dividing as output, another part, In order to keep frequency it is constant, it is desirable to phase contrast does not change, if dephased change, the voltage output of PLL IC The voltage at end changes, and goes to control VCO, until phase contrast recovers, reaches the purpose of lock phase.

Phaselocked loop（PLL）Technology is the frequency combining method being most widely used at present.The electricity that this synthetic method is used Road synthesizes simple than direct-type, and it is to realize phase feedback control so as to realize the closed loop system of frequency-tracking by phase demodulation.Lock Phase frequency source output signal mutually being made an uproar in loop bandwidth mainly affected by reference signal, phase discriminator, frequency divider and frequency dividing ratio, VCO phases are depended primarily on beyond loop bandwidth to make an uproar.Conventional phase locked loops technology is affected by output frequency factor, in reference signal not Under conditions of limited, closed loop feedback system is limited to relation FloorFom+10log of mutually making an uproar (the Fpd)+20log of phase discriminator (Fvco/Fpd), i.e., under the same conditions, output signal（Feedback signal）Higher, the phase noise of signal is poorer.

Utility model content

The purpose of this utility model is to overcome the deficiencies in the prior art, there is provided a kind of Low phase noise interpolation phase-locked loop circuit, By way of more preferable offset source mixing of mutually making an uproar reduces feedback phase demodulation frequency, the phase noise of output frequency signal is improved.Gram Relation FloorFom+10log of mutually making an uproar (Fpd)+20log (Fvco/ that traditional closed-loop feedback system is limited to phase discriminator are taken Fpd)。

The purpose of this utility model is achieved through the following technical solutions：Low phase noise interpolation phase-locked loop circuit, it wraps Include reference circuit, skew source circuit and interpolation phase-locked loop；The reference signal that reference circuit is provided is divided into two-way, all the way for inclined The shifted signal moved required for source circuit life, another road are supplied to interpolation phase-locked loop, interpolation phase-locked loop by feedback signal with Feedback phase demodulation frequency of the low frequency signal produced after skew source signal mixing as whole closed loop circuit.

Described reference circuit includes crystal oscillator, multiple wave filter, amplifier and power divider；The signal Jing that crystal oscillator is produced After filter and amplification, two work(of Jing power dividers is mitogenetic into two paths of signals, all the way for the shifted signal required for skew source circuit life, Another road is supplied to interpolation phase-locked loop.

Described skew source circuit includes harmonic oscillator, switch filter group, multiple wave filter and amplifier；With reference to electricity Abundant frequency component is produced after the first via signal Jing harmonic oscillator that road provides, and institute is extracted through switch filter group The skew source signal of needs, then amplified filtering, further optimize the clutter of offset source, and adjustment signal power to certain value is supplied The mixing of interpolation phase-locked loop is used.

Described interpolation phase-locked loop includes frequency synthesizer, phaselocked loop, voltage controlled oscillator, multiple wave filter, multiple declines Subtract device and multiple amplifiers；Phaselocked loop output arrives voltage controlled oscillator, voltage controlled oscillator by output after filtering to operational amplifier The output amplified filtering of feedback frequency after obtain lower feedback frequency with shifted signal mixing and return to phaselocked loop being formed surely Fixed closed loop, the output frequency of voltage controlled oscillator obtain final output frequency after amplifying filtering.

Described crystal oscillator is super Low phase noise constant-temperature crystal oscillator.

The beneficial effects of the utility model are：This utility model provides a kind of Low phase noise interpolation phase-locked loop circuit, passes through More preferable offset source mixing of mutually making an uproar reduces the mode of feedback phase demodulation frequency, improves the phase noise of output frequency signal.Overcome Traditional closed-loop feedback system is limited to relation FloorFom+10log of mutually making an uproar (the Fpd)+20log (Fvco/Fpd) of phase discriminator, together When under conditions of identical frequency dividing ratio is ensured, it is possible to achieve higher frequency resolution.Overcome conventional phase locked loops in altofrequency Frequency dividing ratio must be increased, so as to reduce frequency resolution.

Description of the drawings

Fig. 1 is Low phase noise interpolation phase-locked loop circuit schematic diagram；

Fig. 2 is reference circuit figure；

Fig. 3 is offset source circuit diagram；

Fig. 4 is interpolation phase-locked loop circuit figure.

Specific embodiment

The technical solution of the utility model, but protection domain of the present utility model are described in further detail below in conjunction with the accompanying drawings It is not limited to described below.

As shown in figure 1, Low phase noise interpolation phase-locked loop circuit, it includes reference circuit, skew source circuit and interpolation phaselocked loop Road；The reference signal that reference circuit is provided is divided into two-way, all the way for the shifted signal required for skew source circuit life, Ling Yilu It is supplied to the low frequency signal that interpolation phase-locked loop, interpolation phase-locked loop are produced after feedback signal is mixed with skew source signal to do For the feedback phase demodulation frequency of whole closed loop circuit.

As shown in Fig. 2 reference circuit includes crystal oscillator, multiple wave filter, amplifier and power divider；The ultralow phases of 100MHz The outfan of constant-temperature crystal oscillator of making an uproar is connected with the input of the first wave filter, and the outfan of the first wave filter is defeated with the first amplifier Enter end connection, the outfan of the first amplifier is connected with the input of the second wave filter, the outfan and power of the second wave filter The input connection of allotter, first outfan and the second outfan of power divider export the signal of 100MHz respectively.It is brilliant Shake after the filtered amplification of signal of generation, two work(of Jing power dividers is mitogenetic into two paths of signals, all the way for skew source circuit life institute The shifted signal of needs, another road are supplied to interpolation phase-locked loop.

As shown in figure 3, skew source circuit includes harmonic oscillator, switch filter group, multiple wave filter and amplifier；Work( The 100MHz signal input harmonic oscillators of the first outfan output of rate allotter, outfan and the switch filter of harmonic oscillator The input connection of ripple device group, the outfan of switch filter group are connected with the input of the 3rd wave filter, the 3rd wave filter Outfan is connected with the input of the 3rd amplifier, and the outfan of the 3rd amplifier is connected with the input of the 4th wave filter, the The outfan of four wave filter is connected with the input of the first attenuator, the first attenuator output 2800MHz, 3000MHz or The shifted signal of 3200MHz.Abundant frequency component is produced after the first via signal Jing harmonic oscillator that reference circuit is provided, Skew source signal required for switch filter group is extracted, then amplified filtering, further optimize the clutter of offset source, Adjustment signal power is used to 2800MHz, 3000MHz or 3200MHz for the mixing of interpolation phase-locked loop.

Switch filter group includes two switches and three wave filter, and the outfan of harmonic oscillator is defeated with first switch Enter end connection, the first outfan of first switch is connected with the first input end of second switch by the 5th wave filter, and first opens The second outfan for closing is connected with the second input of second switch by the 6th wave filter, and the 3rd outfan of first switch leads to Cross the 7th wave filter to be connected with the 3rd input of second switch, the input of the outfan of second switch and the 3rd wave filter connects Connect.Switch filter group realizes the extraction of required skew source signal.

As shown in figure 4, interpolation phase-locked loop includes frequency synthesizer, phaselocked loop, voltage controlled oscillator, multiple wave filter, many Individual attenuator and multiple amplifiers；The 100MHz reference signals of the second outfan output of power divider are input to the 8th filtering Device, the outfan of the 8th wave filter are connected with the reference signal input of phaselocked loop, the outfan and operational amplifier of phaselocked loop Input connection, the outfan of operational amplifier is connected with the input of 3 rank low-pass loop filters, and 3 rank low-pass loops are filtered The outfan of ripple device is connected with the input of voltage controlled oscillator, the input of the frequency output terminal of voltage controlled oscillator and the second attenuator End connection, the outfan of the second attenuator are connected with the input of the 9th wave filter, and the outfan of the 9th wave filter is put with the 4th The input connection of big device, the outfan of the 4th amplifier are connected with the input of the tenth wave filter, the feedback of voltage controlled oscillator Outfan is connected with the input of the 3rd attenuator, and the outfan of the 3rd attenuator is connected with the input of the 5th amplifier, the The outfan of five amplifiers is connected with the input of the 11st wave filter, the outfan and the 4th attenuator of the 11st wave filter Input connects, and the outfan of the 4th attenuator is connected with the feedback input end of frequency synthesizer, the offset source of frequency synthesizer Signal input part is connected with the outfan of the first attenuator, and the input of the outfan of frequency synthesizer and the 12nd wave filter connects Connect, the outfan of the 12nd wave filter is connected with the input of the 6th amplifier, the outfan of the 6th amplifier and the 13rd is filtered The input connection of ripple device, the outfan of the 13rd wave filter are connected with the feedback input end of phaselocked loop.Tenth wave filter is exported Final output frequency.

To operational amplifier, by output after filtering to voltage controlled oscillator, the output of voltage controlled oscillator is anti-for phaselocked loop output Lower feedback frequency obtained with shifted signal mixing after the feedback amplified filtering of frequency return to phaselocked loop to form stable closed loop Loop, the output frequency of voltage controlled oscillator obtain final output frequency after amplifying filtering.

Claims (5)

1. Low phase noise interpolation phase-locked loop circuit, it is characterised in that：It includes reference circuit, skew source circuit and interpolation phaselocked loop Road；The reference signal that reference circuit is provided is divided into two-way, all the way for the shifted signal required for skew source circuit life, Ling Yilu It is supplied to the low frequency signal that interpolation phase-locked loop, interpolation phase-locked loop are produced after feedback signal is mixed with skew source signal to do For the feedback phase demodulation frequency of whole closed loop circuit.

2. Low phase noise interpolation phase-locked loop circuit according to claim 1, it is characterised in that：Described reference circuit includes crystalline substance Shake, multiple wave filter, amplifier and power divider；After the filtered amplification of signal that crystal oscillator is produced, two work(of Jing power dividers Mitogenetic to give birth to required shifted signal for skew source circuit all the way into two paths of signals, another road is supplied to interpolation phase-locked loop.

3. Low phase noise interpolation phase-locked loop circuit according to claim 1, it is characterised in that：Described skew source circuit includes Harmonic oscillator, switch filter group, multiple wave filter and amplifier；The first via signal Jing harmonic wave that reference circuit is provided occurs Abundant frequency component is produced after device, the skew source signal required for switch filter group is extracted, then amplified filter Ripple, further optimizes the clutter of offset source, and adjustment signal power to certain value is used for the mixing of interpolation phase-locked loop.

4. Low phase noise interpolation phase-locked loop circuit according to claim 1, it is characterised in that：Described interpolation phase-locked loop bag Include frequency synthesizer, phaselocked loop, voltage controlled oscillator, multiple wave filter, multiple attenuators and multiple amplifiers；Phaselocked loop output is arrived Operational amplifier, by output after filtering to voltage controlled oscillator, after the amplified filtering of output feedback frequency of voltage controlled oscillator Obtain lower feedback frequency and return to phaselocked loop forming stable closed loop, the output of voltage controlled oscillator with shifted signal mixing Frequency obtains final output frequency after amplifying filtering.

5. Low phase noise interpolation phase-locked loop circuit according to claim 2, it is characterised in that：Described crystal oscillator is super Low phase noise Constant-temperature crystal oscillator.