High frequency low noise phase-frequency detector and phase noise reduction method and apparatus

• US 7,386,286 B2
• Filed: 09/07/2005
• Issued: 06/10/2008
• Est. Priority Date: 06/01/2001
• Status: Expired due to Term

• Current Assignee: ARRIS Enterprises LLC (CommScope Holding Company, Inc.)
• Original Assignee: Broadband Innovations, Inc.
• Inventors: Petrovic, Branislav, Ashkenasi, Maxim
• Primary Examiner(s): Phu; Sanh D.
• Application Number:
  US11/220,399
• Publication Number:
  US 20060057996A1
• Time in Patent Office: 1,007 Days
• Field of Search: 455/165.1, 455/260, 455/264, 455/255, 329/323
• US Class Current: 455/165.1
• CPC Class Codes: H03D 3/007 by converting the oscillations into two quadrature related signals H03D3/245 takes precedence
• CPC Class Codes: H03L 7/085 concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal H03L7/10 takes precedence; circuits for comparing the phase or frequency of two mutually-independent oscillations H03D13/00
• CPC Class Codes: H03L 7/087 using at least two phase detectors or a frequency and phase detector in the loop
• CPC Class Codes: H03L 7/113 using frequency discriminator

Abstract

The present invention discloses a new type of extremely low-noise phase-frequency detector (PFD) 500, broadband from DC to multi-GHz RF frequencies for PLL synthesizer applications. Free of any feedback mechanisms, thus inherently fast, it operates close to transition frequency f_T of IC processes or frequency limits of discrete mixers. The PFD 500 utilizes complex SSB conversion in both the in-phase and quadrature arms, delaying the in-phase arm in 530, beating the delayed signal 124 with the un-delayed quadrature signal 122 in mixer 126. The output 128 contains both the frequency difference and the phase difference information between the two signals 118 and 520, providing both the frequency-discrimination (FD) and the phase detection (PD) functions. Utilizing standard mixers the PFD 500 can achieve superior CNRs of 180 dBc/Hz at multi-GHz RF. Additionally, utilizing the FD/FM demodulation capability, the present invention improves phase noise of various signals and linearity of FM modulators.

Claims

1. A method for providing frequency discrimination/comparison and phase detection/comparison using complex single side-band (SSB) down conversion, the method comprising:

receiving a local oscillator (LO) of frequency ω

_o and phase θ

(t), in-phase and quadrature signals;

receiving a carrier signal of carrier frequency ω

_c and phase φ

(t), in-phase and quadrature signals;

multiplying each of said in-phase and quadrature LO signals with each of said in-phase and quadrature carrier signals, thereby generating four converted signals;

combining in two pairs said four converted signals, to produce the in-phase LSB signal and the quadrature LSB signal;

delaying one of said LSB signals by a time delay τ

to produce a delayed LSB signal;

multiplying said delayed LSB signal with said other LSB signal, to produce the baseband signal BB(t); and

outputting said baseband signal BB(t), wherein said signal BB(t) has a DC voltage component substantially proportional to a frequency difference ω

_c−

ω

_o, and when this frequency difference is substantially near or equal to zero then said output signal BB(t) assumes a DC voltage substantially proportional to a phase difference φ

(t)−

θ

(t).

2. The method of claim 1 wherein the receiving a local oscillator (LO) in-phase and quadrature signals includes receiving and splitting a local oscillator (LO) signal to two signal components:

the in-phase component and the quadrature component.

3. The method of claim 1 wherein the receiving carrier in-phase and quadrature signals includes receiving and splitting an input carrier signal to two signal components:

the in-phase component and the quadrature component.

4. The method of claim 1 comprising an operation of adding or subtracting to effect the combining in two pairs said four converted signals.

5. The method of claim 1 further comprising controlling said time delay τ

.

6. The method of claim 5, further comprising utilizing said output BB(t) to control said time delay τ

in a closed-loop circuit.

7. A device for providing frequency discrimination/comparison and phase detection/comparison using complex single side-band (SSB) down conversion, the device comprising:

an in-phase local oscillator (LO) input providing an in-phase LO signal of frequency ω

_o and phase θ

(t);

a quadrature local oscillator (LO) input providing a quadrature component of said LO signal;

an in-phase carrier frequency signal input providing an in-phase carrier signal component of frequency ω

_c and phase φ

(t);

a quadrature carrier frequency signal input providing a quadrature signal component of said carrier signal;

four multiplying elements multiplying respective ones of said in-phase and quadrature LO components with separate ones of said in-phase and quadrature input carrier components, generating two pairs of different converted input signals;

two combiners to combine respective ones of said two pairs of said converted signals, producing in-phase and quadrature un-delayed lower single sideband (LSB) signals;

a delay element delaying one of the two said un-delayed LSB signals by a time delay τ

, to generate one delayed LSB signal;

a fifth multiplying element multiplying said delayed LSB signal with the other said un-delayed LSB signal, to generate the baseband signal BB(t); and

an output port outputting said baseband signal BB(t), wherein said signal BB(t) has a DC voltage component substantially proportional to a frequency difference ω

_c−

ω

_o, and as this frequency difference approaches zero then said output signal BB(t) assumes a DC voltage substantially proportional to the phase difference φ

(t)−

θ

(t).

8. The device of claim 7 further comprising a splitter circuit for receiving a local oscillator (LO) signal and splitting the LO signal into an in-phase and quadrature signal components.

9. The device of claim 7 further comprising a splitter circuit for receiving a carrier signal and splitting the carrier signal into an in-phase and quadrature signal components.

10. The device of claim 7 wherein the two combiners use adding or subtracting means to effect the combining said two pairs of said converted signals.

11. The device of claim 7 further comprising an adjustable time delay element having a control input to control the parameters of said time delay element.

12. The device of claim 11, comprising circuitry to couple said control input of said adjustable time delay element to said output BB(t), thereby providing a closed-loop adjustment of said time delay element.

13. The device of claim 7, thus further comprising:

a local oscillator (LO) reference signal;

a first splitter splitting the LO reference signal into an in-phase LO component and a quadrature LO component, said in-phase LO component coupled to said in-phase LO input of said device, said quadrature LO component coupled to said quadrature LO input of said device;

a Voltage Controlled Oscillator (VCO) having one tuning voltage input port (V_T), and one output port providing a signal Vosc;

a second splitter splitting said Vosc signal into an in-phase Vosc component and a quadrature Vosc component, said in-phase Vosc component coupled to said in-phase carrier input of said device, said quadrature Vosc component coupled to said quadrature carrier input of said device, and

a loop filter, having one input coupled to said baseband output BB(t) of said device, and one output coupled to said tuning voltage input V_T of said VCO, the device thereby providing a frequency-discriminator and phase-detector (PFD) function in a phase-locked loop (PLL) system.

14. The device of claim 7, further comprising:

a local oscillator (LO) reference input providing a LO reference signal;

a first splitter splitting the LO reference signal into an in-phase LO component and a quadrature LO component, said in-phase LO component coupled to said in-phase LO input of the device, said quadrature LO component coupled to said quadrature LO input of the device;

a Voltage Controlled Oscillator (VCO) having one tuning voltage input port (V_T), and one output port providing a signal Vosc;

a second splitter splitting said Vosc signal into an in-phase Vosc component and a quadrature Vosc component, said in-phase Vosc component coupled to said in-phase carrier input of the device, said quadrature Vosc component coupled to said quadrature carrier input of the device;

an input modulating signal V_mod;

a combiner to combine said baseband signal BB(t) of the device with said input modulating signal V_mod, to produce an error signal; and

a loop filter, having one input coupled to said error signal, and one output coupled to said tuning voltage input V_T of said VCO, thereby providing a linearization function in an FM modulator system.

15. A feed-back system for providing phase noise-reduction (clean-up) of a Voltage Controlled Oscillator (VCO) output signal, comprising:

a VCO generating a signal Vo of frequency ω

_c, having a tuning voltage input V_T, and separated into in-phase and quadrature Vo signal components;

a local oscillator (LO) providing an LO signal of frequency ω

_o close or equal to ω

_c+π

·

n/τ

, where τ

is a delay time and n is an integer 0,±

1,±

2, . . . , and separated into in-phase and quadrature LO signal components;

four multiplying elements multiplying said in-phase and quadrature LO signal components with respective ones of said in-phase and quadrature Vo signal components, generating two pairs of converted signals;

a first and a second combiner to combine respective ones of said two pairs of converted signals, producing an un-delayed lower single sideband (LSB) in-phase and un-delayed LSB quadrature signals;

a first delay element having a time delay comparable to τ

, coupled to said un-delayed in-phase LSB signal, to provide a delayed LSB in-phase signal;

a second delay element having a time delay comparable to τ

, coupled to said un-delayed quadrature LSB signal, to provide a delayed LSB quadrature signal;

a fifth multiplying element for multiplying said delayed LSB in-phase signal with said un-delayed LSB quadrature signal, generating a first multiplication product;

a sixth multiplying element for multiplying said delayed LSB quadrature signal with said un-delayed LSB in-phase signal, generating a second multiplication product;

a third combiner to combine said first and second multiplication products, to produce a demodulated baseband signal BB(t); and

a filter having one input port coupled to said demodulated baseband signal BB(t), and an output port coupled to said tuning voltage input V_T of said VCO.

16. The feed-back system of claim 15, comprising the first and second combiners each including a circuit to add or subtract the respective ones of said two pairs of said converted signals.

17. A feed-back system for providing phase noise-reduction (clean-up) of an input signal, comprising:

an input signal having a frequency ω

_c;

a phase modulator having a first input port, a second input port and one output port, the first input port coupled to said input signal, and the output port providing a signal Vo, and separated into in-phase and quadrature Vo signal components;

a local oscillator (LO) providing an LO signal of frequency ω

₀ close or equal to ω

_c+π

·

n/τ

, where τ

is a delay time and n is an integer 0,±

1,±

2, . . . , and separated into in-phase and quadrature LO signal components;

four multiplying elements multiplying said in-phase and quadrature LO signal components with respective ones of said in-phase and quadrature Vo signal components, generating two pairs of converted signals;

a first and a second combiner to combine respective ones of said two pairs of converted signals, producing an un-delayed lower single sideband (LSB) in-phase and un-delayed LSB quadrature signals;

a first delay element having a time delay comparable to τ

, coupled to said un-delayed in-phase LSB signal, to provide a delayed LSB in-phase signal;

a second delay element having a time delay comparable to τ

, coupled to said un-delayed quadrature LSB signal, to provide a delayed LSB quadrature signal;

a fifth multiplying element for multiplying said delayed LSB in-phase signal with said un-delayed LSB quadrature signal, generating a first multiplication product;

a sixth multiplying element for multiplying said delayed LSB quadrature signal with said un-delayed LSB in-phase signal, generating a second multiplication product;

a third combiner to combine said first and second multiplication products, to produce a demodulated baseband signal BB(t); and

a filter having one input port coupled to said demodulated baseband signal BB(t), and an output port coupled to said second input of said phase modulator.

18. The feed-back system of claim 17, comprising the first and second combiners each including a circuit to add or subtract the respective ones of said two pairs of said converted signals.

19. A feed-forward system for providing phase noise-reduction (clean-up) of an input signal, comprising:

A signal Vc having a frequency ω

_c;

a phase modulator having a first input port, a second input port and one output port, the first input port coupled to said signal Vc and separated into in-phase and quadrature Vc signal components, and the output port providing a signal Vo;

a local oscillator (LO) providing an LO signal of frequency ω

₀ close or equal to ω

_c+π

·

n/τ

, where τ

is a delay time and n an integer 0,±

1,±

2, . . . , and separated into in-phase and quadrature LO signal components;

four multiplying elements multiplying said in-phase and quadrature LO signal components with respective ones of said in-phase and quadrature Vc signal components, generating two pairs of converted signals;

a first and a second combiner to combine respective ones of said two pairs of converted signals, producing an un-delayed lower single sideband (LSB) in-phase and un-delayed LSB quadrature signals;

a first delay element having a time delay comparable to τ

, coupled to said un-delayed in-phase LSB signal, to provide a delayed LSB in-phase signal;

a second delay element having a time delay comparable to τ

, coupled to said un-delayed quadrature LSB signal, to provide a delayed LSB quadrature signal;

a fifth multiplying element for multiplying said delayed LSB in-phase signal with said un-delayed LSB quadrature signal, generating a first multiplication product;

a sixth multiplying element for multiplying said delayed LSB quadrature signal with said un-delayed LSB in-phase signal, generating a second multiplication product;

a third combiner to combine said first and second multiplication products, to produce a demodulated baseband signal BB(t); and

a filter having one input port coupled to said demodulated baseband signal BB(t), and an output port coupled to said second input of said phase modulator.

20. The feed-forward system of claim 19, comprising the first and second combiners each including a circuit to add or subtract the respective ones of said two pairs of said converted signals.

21. A method for providing frequency discrimination/comparison and phase detection/comparison using down conversion, the method comprising:

receiving a local oscillator (LO) of frequency ω

_o and phase θ

(t), in-phase and quadrature signals;

receiving a carrier signal of carrier frequency ω

_c and phase φ

(t), in-phase and quadrature signals;

multiplying said in-phase LO signal with said in-phase carrier signal, and said quadrature LO signal with said quadrature carrier signal, thereby generating two converted signals;

combining said two converted signals, to produce one LSB converted signal;

multiplying one of said quadrature carrier signal or in-phase carrier signal with one of said in-phase LO signal or quadrature LO signal, thereby generating one double side-band (DSB) converted signal;

delaying one of said DSB or LSB converted signals by a time delay τ

to produce a delayed signal;

multiplying said delayed signal with the un-delayed one of said DSB or LSB converted signals, to produce the baseband signal BB(t); and

outputting said baseband signal BB(t), wherein said signal BB(t) has a DC voltage component substantially proportional to a frequency difference ω

_c−

ω

_o, and when this frequency difference is substantially near or equal to zero then said output signal BB(t) assumes a DC voltage substantially proportional to a phase difference φ

(t)−

θ

(t).

22. The method of claim 21 wherein the receiving a local oscillator (LO) in-phase and quadrature signals includes receiving and splitting a local oscillator (LO) signal to two signal components:

the in-phase component and the quadrature component.

23. The method of claim 21 wherein the receiving carrier in-phase and quadrature signals includes receiving and splitting an input carrier signal to two signal components:

the in-phase component and the quadrature component.

24. A method for providing frequency discrimination/comparison and phase detection/comparison using frequency conversion, the method comprising:

receiving a local oscillator (LO) of frequency ω

_o and phase θ

(t);

receiving a carrier signal of carrier frequency ω

_c and phase φ

(t), in-phase and quadrature signals;

multiplying said LO signal with said in-phase carrier signal, thereby generating a first double side-band (DSB) converted signal;

multiplying said LO signal with said quadrature carrier signal, thereby generating a second DSB converted signal;

delaying one of either first or second DSB converted signals by a time delay τ

to produce a delayed signal;

multiplying said delayed signal with other un-delayed said first or second DSB signal, to produce a baseband signal BB(t); and

outputting said baseband signal BB(t), wherein said signal BB(t) has a DC voltage component substantially proportional to a frequency difference ω

_c−

ω

_o, and when this frequency difference is substantially near or equal to zero then said output signal BB(t) assumes a DC voltage substantially proportional to a phase difference φ

(t)−

θ

(t).

25. The method of claim 24 wherein the receiving a carrier in-phase and quadrature signals includes receiving and splitting a carrier signal to two signal components:

the in-phase component and the quadrature component.

26. A device for providing frequency discrimination/comparison and phase detection/comparison using simple conversion, the device comprising:

a local oscillator (LO) input providing a signal of frequency ω

_o and phase θ

(t);

an in-phase carrier signal input providing an in-phase carrier signal of frequency ω

_c and phase φ

(t);

a quadrature carrier frequency signal input providing a quadrature carrier signal component of said carrier signal;

a multiplying element multiplying said LO signal with said in-phase carrier signal, thereby generating a first double side-band (DSB) converted signal;

a multiplying element multiplying said LO signal with said quadrature carrier signal component, thereby generating a second DSB converted signal;

a resistor-capacitor (RC) delay element delaying one of either first or second DSB converted signals to produce a delayed signal;

a multiplying element multiplying said delayed signal with other un-delayed said first or second DSB signal, to produce a baseband signal BB(t); and

an output port outputting said baseband signal BB(t), wherein said signal BB(t) has a DC voltage component substantially proportional to a frequency difference ω

_c−

ω

_o, and when this frequency difference is substantially near or equal to zero then said output signal BB(t) assumes a DC voltage substantially proportional to a phase difference φ

(t)−

θ

(t).

27. The device of claim 26 further comprising a splitter circuit for receiving a carrier signal and splitting the carrier signal into an in-phase and quadrature signal components.

28. The device of claim 26, further comprising:

a local oscillator (LO) input providing a LO reference signal, coupled to the local oscillator (LO) input of the device;

a Voltage Controlled Oscillator (VCO) having one tuning voltage input port (V_T), and one output port providing a signal Vosc;

a splitter splitting said Vosc signal into an in-phase Vosc component and a quadrature Vosc component, said in-phase Vosc component coupled to said in-phase carrier input of the device, said quadrature Vosc component coupled to said quadrature carrier input of the device; and

a loop filter, having one input coupled to baseband signal output BB(t) of the device, and one output coupled to said tuning voltage input V_T of said VCO, thereby creating a closed loop system able to provide both frequency acquisition and phase lock.