Oscillators having arbitrary frequencies and related systems and methods

• US 8,228,127 B2
• Filed: 03/10/2010
• Issued: 07/24/2012
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Sand 9, Inc. (Analog Devices, Inc.)
• Inventors: Rebel, Reimund, Schoepf, Klaus Juergen, Kuypers, Jan H.
• Primary Examiner(s): Goodley, James E
• Application Number:
  US12/721,472
• Publication Number:
  US 20110151856A1
• Time in Patent Office: 867 Days
• Field of Search: 331/16, 331/17, 455/164.1, 455/182.1, 455/192.1
• US Class Current: 331/17
• CPC Class Codes: H03B 19/00 Generation of oscillations by non-regenerative frequency multiplication or division of a signal from a separate source transference of modulation from one carrier to another H03D7/00
• CPC Class Codes: H03B 5/30 with frequency-determining element being electromechanical resonator
• CPC Class Codes: H03B 5/32 being a piezoelectric resonator selection of piezoelectric material H10N30/00
• CPC Class Codes: H03C 3/095 applying frequency modulation to the loop in front of the voltage controlled oscillator
• CPC Class Codes: H03J 7/065 the counter or frequency divider being used in a phase locked loop
• CPC Class Codes: H03L 7/0991 the oscillator being a digital oscillator, e.g. composed of a fixed oscillator followed by a variable frequency divider H03L7/0995 takes precedence; fixed oscillators with means for selecting among various phases H03L7/0814
• CPC Class Codes: H03L 7/18 using a frequency divider or counter in the loop H03L7/20, H03L7/22 take precedence
• CPC Class Codes: H03L 7/197 a time difference being used for locking the loop, the counter counting between numbers which are variable in time or the frequency divider dividing by a factor variable in time, e.g. for obtaining fractional frequency division H03L7/1806 takes precedence
• CPC Class Codes: H04B 1/40 Circuits

Abstract

Systems and methods for operating with oscillators configured to produce an oscillating signal having an arbitrary frequency are described. The frequency of the oscillating signal may be shifted to remove its arbitrary nature by application of multiple tuning signals or values to the oscillator. Alternatively, the arbitrary frequency may be accommodated by adjusting operation one or more components of a circuit receiving the oscillating signal.

Claims

1. A method comprising:

downconverting a cellular telephone signal, the cellular telephone signal modulated with data, using an oscillating reference signal having an arbitrary frequency to generate a downconverted signal including the data;

sampling the downconverted signal with an analog-to-digital converter (ADC) using a sampling rate selected to induce a shift of the data of the downconverted signal in a frequency domain; and

receiving an indication of a value of the arbitrary frequency and selecting the sampling rate of the ADC in response to receiving the indication,

wherein receiving the indication comprises receiving the indication from memory of an oscillator.

2. The method of claim 1, further comprising receiving the cellular telephone signal modulated with data.

3. The method of claim 1, further comprising receiving, from the oscillator, the oscillating reference signal having an arbitrary frequency, the oscillator having a mechanical resonator.

4. The method of claim 1, further comprising generating the oscillating reference signal from an oscillator output signal of the oscillator.

5. The method of claim 4, wherein generating the oscillating reference signal comprises receiving, from the oscillator, the oscillator output signal at a frequency synthesizer and synthesizing the oscillating reference signal, wherein the oscillating reference signal differs in frequency from a frequency of the oscillator output signal, and wherein the oscillator has a mechanical resonator.

6. The method of claim 5, wherein the frequency synthesizer is a phase-locked loop (PLL).

7. A method comprising:

downconverting a first signal, the first signal modulated with data, using an oscillating reference signal having an arbitrary frequency to generate a downconverted signal including the data;

sampling the downconverted signal with an analog-to-digital converter (ADC) to produce a digital signal including digital data corresponding to the data;

shifting, using a digital signal processor (DSP), the digital data in a frequency domain; and

receiving an indication of a value of the arbitrary frequency and, in response to receiving the indication, selecting an amount by which to shift the digital data in the frequency domain using the DSP,

wherein receiving the indication comprises receiving the indication from memory of an oscillator.

8. The method of claim 7, further comprising receiving the first signal modulated with data.

9. The method of claim 7, further comprising receiving, from the oscillator, the oscillating reference signal having an arbitrary frequency, the oscillator having a mechanical resonator.

10. The method of claim 7, further comprising generating the oscillating reference signal from an oscillator output signal of the oscillator.

11. The method of claim 10, wherein generating the oscillating reference signal comprises receiving, from the oscillator, the oscillator output signal at a frequency synthesizer and synthesizing the oscillating reference signal, wherein the oscillating reference signal differs in frequency from a frequency of the oscillator output signal, and wherein the oscillator has a mechanical resonator.

12. The method of claim 11, wherein the frequency synthesizer is a phase-locked loop (PLL).

13. The method of claim 7, wherein the first signal is a cellular telephone signal.

14. The method of claim 7, wherein the arbitrary frequency differs from a standard oscillator frequency and wherein sampling the downconverted signal with an ADC comprises using a sampling rate corresponding to the standard oscillator frequency.

15. The method of claim 14, wherein the first signal is modulated with analog data, and further comprising:

applying the digital signal to a carrier tracking loop.

16. The method of claim 15, wherein the carrier tracking loop comprises a numerically controlled oscillator (NCO) configured to digitally shift the digital data in a frequency domain.

17. The method of claim 15, wherein the first signal is a cellular telephone signal modulated with cellular telephone data.

18. The method of claim 15, wherein the first signal is a global positioning system (GPS) signal.