CN105322961A - Injection locking type dual-mode prescaler with low power consumption and wide locking range - Google Patents

Abstract

The invention provides an injection locking type dual-mode prescaler with low power consumption and a wide locking range. The injection locking type dual-mode prescaler comprises N+1 stages of annular oscillators, a first mode control switch and a second mode control switch, wherein N is an even number greater than 0; the first mode control switch and the second mode control switch are electrically connected with the (N+1)th stage of oscillator in the N+1 stages of annular oscillators and are suitable for controlling a frequency dividing ratio of the injection locking type dual-mode prescaler with low power consumption and the wide locking range. The injection locking type dual-mode prescaler with low power consumption and the wide locking range has the characteristics of low power consumption and high input frequency; the connected tuning capacitance is controlled by the switches, so that the input frequency range of the injection locking type dual-mode prescaler with low power consumption and the wide locking range can be enlarged.

Description

The injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption

Technical field

The invention belongs to wireless lan communication lsi technical field, particularly the injection locking formula dual-modulus prescaler of the wide lock-in range of a kind of low-power consumption.

Background technology

In field of wireless communication, phase-locked loop (PhaseLockLoop, PLL) is widely used in, among filtering, frequency synthesis, modulation /demodulation, input, becoming the basic element of character that communication field is indispensable.

Most phase-locked loops adopts pre-divider to realize frequency division at feedback path.But along with the increase of operating frequency, the power consumption of pre-divider also constantly promotes, become except voltage controlled oscillator (VoltageControlledOscillator, VCO) outward, the parts consumed energy most in whole PLL.Therefore, reducing the power consumption of pre-divider, is the effective way realizing PLL low power dissipation design.

In existing pre-divider technology, current mode logic frequency divider (MOSCurrentModeLogic, MCML) has the advantage of input wideband, but consumed power is excessive.And traditional injection locking frequency splitting technology, compared to MCML, have the advantages that energy consumption is low under same frequency, but incoming frequency is range limited.Its frequency dividing ratio additional cannot change, and traditional injection locking frequency splitting technology is seldom applied in the middle of pre-divider.

In sum, design and can provide variable frequency dividing ratio, and meet low in energy consumption, frequency is high, the pre-divider of wide incoming frequency scope, becomes a large difficult point.

Summary of the invention

The present invention is directed to prior art above shortcomings, propose the injection locking formula dual-modulus prescaler of the wide lock-in range of a kind of low-power consumption, for solving the problem that power is high, frequency is low and incoming frequency is range limited that pre-divider of the prior art exists.

For achieving the above object and other relevant objects, the invention provides the injection locking formula dual-modulus prescaler of the wide lock-in range of a kind of low-power consumption, comprising:

N+1 level ring oscillator, N be greater than 0 even number;

First mould control switch and the second mould control switch, be electrically connected with the N+1 level in described N+1 level ring oscillator, is suitable for the injection locking formula dual-modulus prescaler frequency dividing ratio controlling the wide lock-in range of described low-power consumption.

As a kind of preferred version of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, every one-level of described N+1 level ring oscillator includes NMOS tube and PMOS, wherein,

In every one-level, the source ground of NMOS tube, grid access injected frequency signal Fin; The source electrode access Vdd of PMOS, drain electrode is electrically connected the output as this grade with the drain electrode of NMOS tube;

The output of previous stage is connected to the input of grid as next stage of the PMOS in next stage, and the output of the N+1 level in described N+1 level ring oscillator is connected to the input of grid as the first order of the PMOS in the first order in described N+1 level ring oscillator.

As a kind of preferred version of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, described first mould control switch is PMOS switch pipe, and described second mould control switch is nmos switch pipe;

The source electrode of described PMOS switch pipe is electrically connected with the grid of the PMOS in the N+1 level in described N+1 level ring oscillator, the source electrode access injected frequency signal Fin of described nmos switch pipe, the grid of described PMOS switch pipe and the grid of described nmos switch pipe are all electrically connected with mould control signal MC, and the drain electrode of described PMOS switch pipe and the drain electrode of described nmos switch pipe are all electrically connected with the grid of the NMOS tube in the N+1 level in described N+1 level ring oscillator.

As a kind of preferred version of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, described first mould control switch and described second mould control switch control by described mould control signal MC;

When described mould control signal MC is low level, described first mould control switch conduction, described second mould control switch OFF, the grid of NMOS tube in the N+1 level in described N+1 level ring oscillator and the grid of PMOS all access the output of the N level in described N+1 level ring oscillator;

When described mould control signal MC is high level, described first mould control switch OFF, described second mould control switch conduction, the grid access injected frequency signal Fin of the NMOS tube in the N+1 level in described N+1 level ring oscillator, the grid of PMOS accesses the output of the N level in described N+1 level ring oscillator.

As a kind of preferred version of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption also comprises tuning capacitance, described tuning capacitance is electrically connected with the output of i-th grade in described N+1 level ring oscillator, be suitable for regulating the phase delay of i-th grade in described N+1 level ring oscillator, to improve input bandwidth, wherein, 1≤i≤N.

As a kind of preferred version of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption also comprises the 3rd mould control switch, and described 3rd mould control switch is nmos switch pipe; The grid of described nmos switch pipe is electrically connected with mould control signal MC, and drain electrode is electrically connected with described tuning capacitance, source ground; One end of described tuning capacitance is electrically connected with the drain electrode of described nmos switch pipe, and the other end is electrically connected with the output of i-th grade in described N+1 level ring oscillator.

As a kind of preferred version of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, described 3rd mould control switch controls by described mould control signal MC: when described mould control signal MC is high level, described 3rd mould control switch conduction, described tuning capacitance accesses described N+1 level ring oscillator; When described mould control signal MC is low level, described 3rd mould control switch OFF, described tuning capacitance does not access described N+1 level ring oscillator.

As a kind of preferred version of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, the capacitance Ca of described tuning capacitance meets:

$C_a=C_0+\frac{1}{{\mathrm{\ω}}_0{R}_0}tan(N.arctan({\mathrm{\ω}}_0{R}_0{C}_0\left)\right)$

Wherein, C ₀for the electric capacity of the every one-level in described N+1 level ring oscillator, R ₀for the resistance of the every one-level in described N+1 level ring oscillator, ω ₀frequency when frequency dividing ratio for the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1.

The feature with low-power consumption, high incoming frequency of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, access tuning capacitance by switch control rule, the incoming frequency scope of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption can be increased.

Accompanying drawing explanation

Fig. 1 is shown as the structural representation of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention.

Fig. 2 is shown as the small-signal analysis figure of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention.

The 4/5 dual-modulus prescaler input waveform that Fig. 3 realizes when being shown as the injection locking formula dual-modulus prescaler N=4 of the wide lock-in range of low-power consumption of the present invention and frequency dividing ratio are respectively oscillogram when 4 and 5.

Element numbers explanation

The first order in 1N+1 level ring oscillator

The second level in 2N+1 level ring oscillator

The third level in 3N+1 level ring oscillator

N+1 level in 4N+1 level ring oscillator

5 first mould control switches

6 second mould control switches

7 the 3rd mould control switches

8 tuning capacitances

Embodiment

Below by way of specific instantiation, embodiments of the present invention are described, those skilled in the art the content disclosed by this specification can understand other advantages of the present invention and effect easily.The present invention can also be implemented or be applied by embodiments different in addition, and the every details in this specification also can based on different viewpoints and application, carries out various modification or change not deviating under spirit of the present invention.

Refer to Fig. 1 to Fig. 3.It should be noted that, the diagram provided in the present embodiment only illustrates basic conception of the present invention in a schematic way, though only show the assembly relevant with the present invention in diagram but not component count, shape and size when implementing according to reality is drawn, it is actual when implementing, and the kenel of each assembly, quantity and ratio can be a kind of change arbitrarily, and its assembly layout kenel also may be more complicated.

Refer to Fig. 1, the invention provides the injection locking formula dual-modulus prescaler of the wide lock-in range of a kind of low-power consumption, the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption comprises:

N+1 level ring oscillator, N be greater than 0 even number;

First mould control switch 5 and the second mould control switch 6, described first mould control switch 5 and described second mould control switch 6 are electrically connected with described oscillator N+1 level 4, are suitable for the injection locking formula dual-modulus prescaler frequency dividing ratio controlling the wide lock-in range of described low-power consumption.

Exemplarily, in described N+1 level ring oscillator, the second level 2 in the first order 1 in described N+1 level ring oscillator, described N+1 level ring oscillator, the third level 3 in described N+1 level ring oscillator include NMOS tube 12 and PMOS 11 to every one-level of the N+1 level in described N+1 level ring oscillator, wherein, in every one-level, the source ground of NMOS tube 12, grid access injected frequency signal Fin; The source electrode access power end Vdd of PMOS 11, drain electrode is electrically connected the output as this grade with the drain electrode of NMOS tube 12; The output of previous stage is connected to the input of grid as next stage of PMOS 11 in next stage, and the output of the N+1 level 4 in described N+1 level ring oscillator is connected to the input of grid as the first order 1 in described N+1 level ring oscillator of the PMOS in the first order 1 in described N+1 level ring oscillator.

Exemplarily, described first mould control switch 5 is PMOS switch pipe, and described second mould control switch 6 is nmos switch pipe; The source electrode of described PMOS switch pipe is electrically connected with the grid of the PMOS 11 in the N+1 level 4 in described N+1 level ring oscillator, the source electrode access injected frequency signal Fin of described nmos switch pipe, the grid of described PMOS switch pipe and the grid of described nmos switch pipe are all electrically connected with mould control signal MC, and the drain electrode of described PMOS switch pipe and the drain electrode of described nmos switch pipe are all electrically connected with the grid of the NMOS tube 12 in the N+1 level 4 in described N+1 level ring oscillator.

Exemplarily, described first mould control switch 5 and described second mould control switch 6 control by described mould control signal MC; Concrete control mode is: when described mould control signal MC is low level (being numeral 0), described first mould control switch 5 conducting, described second mould control switch 6 turns off, the grid of NMOS tube 12 in N+1 level 4 in described N+1 level ring oscillator and the grid of PMOS 11 all access the output of the N level in described N+1 level ring oscillator; Now, N+1 level in described N+1 level ring oscillator accesses in the circuit of injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption with the form of inverter, and the frequency dividing ratio of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N; When described mould control signal MC is high level (being numeral 1), described first mould control switch 5 turns off, described second mould control switch 6 conducting, the grid access injected frequency signal Fin of the NMOS tube 12 in the N+1 level 4 in described N+1 level ring oscillator, the grid of the PMOS 11 in the N+1 level 4 in described N+1 level ring oscillator accesses the output of the N level in described N+1 level ring oscillator, now, the frequency dividing ratio of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1.

Exemplarily, the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption also comprises tuning capacitance 8, described tuning capacitance 8 is electrically connected with the output of i-th grade in described N+1 level ring oscillator, be suitable for regulating the phase delay of i-th grade in described N+1 level ring oscillator, to improve input bandwidth, wherein, 1≤i≤N; In Fig. 1, be electrically connected exemplarily with the output of described tuning capacitance 8 with the 2nd grade in described N+1 level ring oscillator, but actual conditions are not as limit.

More specifically, the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption also comprises the 3rd mould control switch 7, and described 3rd mould control switch 7 is nmos switch pipe; The grid of described nmos switch pipe is electrically connected with mould control signal MC, and drain electrode is electrically connected with described tuning capacitance 8, source ground; And one end of described tuning capacitance 8 is electrically connected with the drain electrode of described nmos switch pipe 7, the other end is electrically connected with the output of i-th grade in described N+1 level ring oscillator.

Exemplarily, described 3rd mould control switch 7 controls by described mould control signal MC, concrete control method is: when described mould control signal MC is high level (being numeral 1), described 3rd mould control switch 7 conducting, described tuning capacitance 8 accesses described N+1 level ring oscillator, changes the phase delay of i-th grade; When described mould control signal MC is low (namely numeral is 0), described 3rd mould control switch 7 turns off, and described tuning capacitance 8 does not access described N+1 level ring oscillator.

If there is no described tuning capacitance 8, when the frequency dividing ratio of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1, circuit is to normal work, and when the frequency dividing ratio compared to the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N, incoming frequency raises.If add described tuning capacitance 8, can maintain former incoming frequency basis on, the phase place that whole circuit delay is produced still keep 180 degree constant.Thus, be equivalent to the scope extending the incoming frequency when the frequency dividing ratio of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1, namely when the frequency dividing ratio of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1 and N, incoming frequency scope when the two circuit normally works is roughly the same, that is, when the frequency dividing ratio of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1 and N, the total frequency band that circuit can normally work increases.

Exemplarily, the capacitance Ca of described tuning capacitance 8 meets:

$C_a=C_0+\frac{1}{{\mathrm{\ω}}_0{R}_0}tan(N.arctan({\mathrm{\ω}}_0{R}_0{C}_0\left)\right)$

Wherein, C ₀for the electric capacity of the every one-level in described N+1 level ring oscillator, R ₀for the resistance of the every one-level in described N+1 level ring oscillator, ω ₀frequency when frequency dividing ratio for the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1.

Operation principle and the design principle of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention are as follows:

When the control voltage of described mould control signal MC is low level, namely the frequency dividing ratio of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is under the pattern of N, as Fig. 2 carries out small-signal analysis, according to Barkhausen decision criteria, the delay phase demand fulfillment of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption:

(N-1)arctan(ω _NR ₀C ₀)+arctan(ω _NR ₀(C ₀+C _L,N+1))＝π

Wherein, C ₀for the electric capacity that the every one-level in described N+1 level ring oscillator is entered viewed from output, R ₀for the resistance that the every one-level in described N+1 level ring oscillator is entered viewed from output, C ₀and R ₀numerical value determined by the size of the technique adopted and PMOS 11, NMOS tube 12; C _{l, N+1}for the input capacitance of the N+1 level in the described N+1 level ring oscillator that accesses with inverter version, as the load of the N level in described N+1 level ring oscillator, count in the phase delay of the N level in described N+1 level ring oscillator; ω _nfrequency when frequency dividing ratio for the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N.

When the control voltage of described module by signal MC is high level, namely the frequency dividing ratio of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is under the pattern of N+1, described tuning capacitance 8 accesses in described N+1 level ring oscillator, now, the delay phase demand fulfillment of the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption:

$Narctan\left({\mathrm{\ω}}_{N+1}^{new}{R}_0{C}_0\right)+arctan\left({\mathrm{\ω}}_{N+1}^{new}{R}_0\right(C_0+C_a\left)\right)=\mathrm{\π}$

Wherein, C ₀for the electric capacity that the every one-level in described N+1 level ring oscillator is entered viewed from output, R ₀for the resistance that the every one-level in described N+1 level ring oscillator is entered viewed from output, C ₀and R ₀numerical value determined by the size of the technique adopted and PMOS 11, NMOS tube 12; C _afor the electric capacity of described tuning capacitance 8; frequency when frequency dividing ratio for the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1.

Reach maximum to inject frequency range under making two kinds of patterns, the total frequency band that namely under two kinds of patterns, circuit can normally work reaches maximum, demand fulfillment can obtain thus:

$C_a=C_0+\frac{1}{{\mathrm{\ω}}_0{R}_0}tan(N.arctan({\mathrm{\ω}}_0{R}_0{C}_0\left)\right)$

Wherein, C ₀for the electric capacity of the every one-level in described N+1 level ring oscillator, R ₀for the resistance of the every one-level in described N+1 level ring oscillator, ω ₀the frequency of the frequency when frequency dividing ratio for the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1.

That is, as the electric capacity C of described tuning capacitance 8 _ameet following condition:

$C_a=C_0+\frac{1}{{\mathrm{\ω}}_0{R}_0}tan(N.arctan({\mathrm{\ω}}_0{R}_0{C}_0\left)\right)$

Inject frequency range under can making two kinds of patterns and reach maximum, the total frequency band that namely under two kinds of patterns, circuit can normally work reaches maximum, thus can increase the incoming frequency scope of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption.

Oscillogram when the 4/5 dual-modulus prescaler input waveform realized when N=4 and frequency dividing ratio are respectively 4 and 5 as shown in Figure 3, wherein, the oscillogram that a is the frequency dividing ratio of injection locking formula 4/5 dual-modulus prescaler of low-power consumption wide lock-in range when being 5, the oscillogram that b is the frequency dividing ratio of injection locking formula 4/5 dual-modulus prescaler of low-power consumption wide lock-in range when being 4, c is the input waveform figure of the frequency dividing ratio of injection locking formula 4/5 dual-modulus prescaler of the wide lock-in range of low-power consumption, wherein, incoming frequency f _in=11.5GHz.

In sum, the invention provides the injection locking formula dual-modulus prescaler of the wide lock-in range of a kind of low-power consumption, comprising: N+1 level ring oscillator, N be greater than 0 even number; First mould control switch and the second mould control switch, be electrically connected with the N+1 level in described N+1 level ring oscillator, is suitable for the injection locking formula dual-modulus prescaler frequency dividing ratio controlling the wide lock-in range of described low-power consumption.The feature with low-power consumption, high incoming frequency of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption of the present invention, access tuning capacitance by switch control rule, the incoming frequency scope of the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption can be increased.

Above-described embodiment is illustrative principle of the present invention and effect thereof only, but not for limiting the present invention.Any person skilled in the art scholar all without prejudice under spirit of the present invention and category, can modify above-described embodiment or changes.Therefore, such as have in art usually know the knowledgeable do not depart from complete under disclosed spirit and technological thought all equivalence modify or change, must be contained by claim of the present invention.

Claims (8)

1. an injection locking formula dual-modulus prescaler for the wide lock-in range of low-power consumption, is characterized in that, comprising:

N+1 level ring oscillator, N be greater than 0 even number;

First mould control switch and the second mould control switch, be electrically connected with the N+1 level in described N+1 level ring oscillator, is suitable for the injection locking formula dual-modulus prescaler frequency dividing ratio controlling the wide lock-in range of described low-power consumption.

2. the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption according to claim 1, is characterized in that: every one-level of described N+1 level ring oscillator includes NMOS tube and PMOS, wherein,

In every one-level, the source ground of NMOS tube, grid access injected frequency signal Fin; The source electrode access Vdd of PMOS, drain electrode is electrically connected the output as this grade with the drain electrode of NMOS tube;

The output of previous stage is connected to the input of grid as next stage of the PMOS in next stage, and the output of the N+1 level in described N+1 level ring oscillator is connected to the input of grid as the first order of the PMOS in the first order in described N+1 level ring oscillator.

3. the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption according to claim 1, is characterized in that: described first mould control switch is PMOS switch pipe, and described second mould control switch is nmos switch pipe;

The source electrode of described PMOS switch pipe is electrically connected with the grid of the PMOS in the N+1 level in described N+1 level ring oscillator, the source electrode access injected frequency signal Fin of described nmos switch pipe, the grid of described PMOS switch pipe and the grid of described nmos switch pipe are all electrically connected with mould control signal MC, and the drain electrode of described PMOS switch pipe and the drain electrode of described nmos switch pipe are all electrically connected with the grid of the NMOS tube in the N+1 level in described N+1 level ring oscillator.

4. the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption according to claim 3, is characterized in that: described first mould control switch and described second mould control switch control by described mould control signal MC;

When described mould control signal MC is low level, described first mould control switch conduction, described second mould control switch OFF, the grid of NMOS tube in the N+1 level in described N+1 level ring oscillator and the grid of PMOS all access the output of the N level in described N+1 level ring oscillator;

When described mould control signal MC is high level, described first mould control switch OFF, described second mould control switch conduction, the grid access injected frequency signal Fin of the NMOS tube in the N+1 level in described N+1 level ring oscillator, the grid of PMOS accesses the output of the N level in described N+1 level ring oscillator.

5. the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption according to any one of claim 1 to 4, it is characterized in that: also comprise tuning capacitance, described tuning capacitance is electrically connected with the output of i-th grade in described N+1 level ring oscillator, be suitable for regulating the phase delay of i-th grade in described N+1 level ring oscillator, to improve input bandwidth, wherein, 1≤i≤N.

6. the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption according to claim 5, is characterized in that: also comprise the 3rd mould control switch, and described 3rd mould control switch is nmos switch pipe; The grid of described nmos switch pipe is electrically connected with mould control signal MC, and drain electrode is electrically connected with described tuning capacitance, source ground; One end of described tuning capacitance is electrically connected with the drain electrode of described nmos switch pipe, and the other end is electrically connected with the output of i-th grade in described N+1 level ring oscillator.

7. the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption according to claim 6, it is characterized in that: described 3rd mould control switch controls by described mould control signal MC: when described mould control signal MC is high level, described 3rd mould control switch conduction, described tuning capacitance accesses described N+1 level ring oscillator; When described mould control signal MC is low level, described 3rd mould control switch OFF, described tuning capacitance does not access described N+1 level ring oscillator.

8. the injection locking formula dual-modulus prescaler of the wide lock-in range of low-power consumption according to claim 5, is characterized in that: the capacitance Ca of described tuning capacitance meets:

$C_a=C_0+\frac{1}{{\mathrm{\ω}}_0{R}_0}\tan (N.\arctan ({\mathrm{\ω}}_0{R}_0{C}_0\left)\right)$

Wherein, C ₀for the electric capacity of the every one-level in described N+1 level ring oscillator, R ₀for the resistance of the every one-level in described N+1 level ring oscillator, ω ₀frequency when frequency dividing ratio for the injection locking formula dual-modulus prescaler of the wide lock-in range of described low-power consumption is N+1.