Local oscillation generator and associated communication system and method for local oscillation generation

Patent metadata

Field	Value
Publication number	US-9300507-B2
Application number	US-201313940416-A
Country	US
Kind code	B2
Filing date	Jul 12, 2013
Priority date	Jul 24, 2012
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

A local oscillation generator includes an oscillation circuit, a frequency multiplication circuit, a mixer, and a frequency divider. The oscillation circuit provides a fundamental oscillation signal. The frequency multiplication circuit provides a first oscillation signal according to the fundamental oscillation signal. The mixer provides a mixed oscillation signal according to mixing of the fundamental oscillation signal and the first oscillation signal. The frequency divider frequency divides the mixed oscillation signal so that the local oscillation generator accordingly provides a local oscillation signal.

First claim

What is claimed is:

1. A local oscillation generator, applied to a communication system, for providing a local oscillation signal, the local oscillation generator comprising:
an oscillation circuit, configured to provide a fundamental oscillation signal with a fundamental frequency;
a frequency multiplication circuit, coupled to the oscillation circuit, configured to multiply the fundamental oscillation signal to generate a first oscillation signal with a first frequency;
a mixer, coupled to the oscillation circuit and the frequency multiplication circuit, said mixer receiving the fundamental oscillation signal and the first oscillation signal, and configured to provide a mixed oscillation signal with a mixer frequency according to the fundamental oscillation signal and the first oscillation signal; and
a frequency divider, coupled to the mixer, configured for frequency-dividing the mixed oscillation signal to provide a frequency-divided signal with a divider frequency.

2. The local oscillation generator according to claim 1 , wherein the local oscillation signal is derived from the frequency-divided signal, and the fundamental frequency is a non-integral multiple of a local oscillation frequency of the local oscillation signal that mitigates interference to said oscillation circuit caused by multi-frequency harmonics of a power amplifier downstream from said frequency divider.

3. The local oscillation generator according to claim 2 , wherein the oscillation circuit and the frequency multiplication circuit are integrated in an oscillator, the fundamental oscillation signal is provided by differential nodes of the oscillator, and the first oscillation signal is provided by a common mode node of the oscillator.

4. The local oscillation generator according to claim 2 , wherein the first frequency is a first integer M multiple of the fundamental frequency, the mixer frequency is a second integer N multiple of the divider frequency, and the second integer N is a non-integral multiple of a sum of the first integer M and 1.

5. The local oscillation generator according to claim 1 , further comprising:
a second frequency multiplication circuit, coupled between the oscillation circuit and the mixer, configured to multiply the fundamental oscillation signal to generate a second oscillation signal with a second frequency.

6. The local oscillation generator according to claim 5 , wherein the first frequency is a first integer M multiple of the fundamental frequency, the second frequency is a second integer L multiple of the fundamental frequency, the mixer frequency is a third integer N multiple of the divider frequency, and the third integer N is a non-integral multiple of a sum of the first integer M and the second integer L.

7. The local oscillation generator according to claim 5 , wherein the fundamental frequency is a first integer M multiple of the first frequency, the second frequency is a second integer L multiple of the fundamental frequency, the mixer frequency is a third integer N multiple of the divider frequency, and the third integer N is a non-integral multiple of a sum of a reciprocal 1 /M of the first integer M and the second integer L.

8. The local oscillation generator according to claim 5 , wherein the first frequency is a first integer M multiple of the fundamental frequency, the fundamental frequency is a second integer L multiple of the second frequency, the mixer frequency is a third integer N multiple of the divider frequency, and the third integer N is a non-integral multiple of a sum of the first integer M and a reciprocal 1 /L of the second integer L.

9. The local oscillation generator according to claim 5 , wherein the fundamental frequency is a first integer M multiple of the first frequency, the fundamental frequency is a second integer L multiple of the second frequency, the mixer frequency is a third integer N multiple of the divider frequency, and the third integer N is a non-integral multiple of a sum of a reciprocal 1 /M of the first integer M and a reciprocal 1 /L of the second integer L.

10. The local oscillation generator according to claim 1 , further comprising:
a filter with a pass band, coupled to the frequency divider, for performing band-pass filtering on the frequency-divided signal,
wherein, said pass band is associated with a frequency of the local oscillation signal.

11. The local oscillation generator according to claim 1 , wherein the mixer supports a band-pass filter function having a pass band associated with the mixer frequency.

12. A communication system, comprising a local oscillation generator for providing a local oscillation signal, the local oscillation generator comprising:
an oscillation circuit, configured to provide a fundamental oscillation signal with a fundamental frequency;
a frequency multiplication circuit, coupled to the oscillation circuit, configured to multiply the fundamental oscillation signal to generate a first oscillation signal with a first frequency;
a mixer, coupled to the oscillation circuit and the frequency multiplication circuit, receiving the fundamental oscillation signal and the first oscillation signal, said mixer configured to provide a mixed oscillation signal with a mixer frequency according to the fundamental oscillation signal and the first oscillation signal; and
a frequency divider, coupled to the mixer, configured for frequency-dividing the mixed oscillation signal to provide a frequency-divided signal with a divider frequency.

13. The communication system according to claim 12 , further comprising a transmitter, to which the local oscillation generator is applied; wherein the local oscillation signal is derived from the frequency-divided signal, and the fundamental frequency is a non-integral multiple of a local oscillation frequency of the local oscillation signal that mitigates interference to said oscillation circuit caused by multi-frequency harmonics of a power amplifier of said transmitter.

14. The communication system according to claim 13 , wherein the first frequency is a first integer M multiple of the fundamental frequency, the mixer frequency is a second integer N multiple of the divider frequency, and the second integer N is a non-integral multiple of a sum of the first integer M and 1 .

15. The communication system according to claim 13 , further comprising:
a second frequency multiplication circuit, coupled between the oscillation circuit and the mixer, configured to multiply the fundamental oscillation signal to generate a second oscillation signal with a second frequency.

16. The communication system according to claim 13 , wherein the first frequency is a first integer M multiple of the fundamental frequency, the second frequency is a second integer N multiple of the fundamental frequency, the mixer frequency is a third integer L multiple of the divider frequency, and the third integer L is a non-integral multiple of a sum of the first integer M and the second integer N.

17. The communication system according to claim 13 , wherein the fundamental frequency is a first integer M multiple of the first frequency, the second frequency is a second integer N multiple of the fundamental frequency, the mixer frequency is a third integer L multiple of the divider frequency, and the third integer L is a non-integral multiple of a sum of a reciprocal 1 /M of the first integer M and the second integer N.

18. The communication system according to claim 13 , wherein the first frequency is a first integer M multiple of the fundamental frequency, the fundamental fre

Assignees

• Mstar Semiconductor Inc

Inventors

• Chang Keng-Meng
• Wang Yao-Chi

Classifications

• H04L27/127 Primary

  using a controlled oscillator in a feedback loop · CPC title

• H03F2200/114

  the amplifier comprising means for electro-magnetic interference [EMI] protection · CPC title

• H03F1/26

  Modifications of amplifiers to reduce influence of noise generated by amplifying elements · CPC title

• H03C3/0908 Primary

  using a phase locked loop · CPC title