Simplified high frequency tuner and tuning method

• US 8,355,683 B2
• Filed: 03/30/2010
• Issued: 01/15/2013
• Est. Priority Date: 09/13/1996
• Status: Expired due to Fees

• Current Assignee: Washington Research Foundation (University of Washington)
• Original Assignee: University of Washington
• Inventors: Suominen, Edwin A.
• Primary Examiner(s): Jackson, Blane J
• Application Number:
  US12/749,742
• Publication Number:
  US 20100184394A1
• Time in Patent Office: 1,022 Days
• Field of Search: 455/130, 455/255, 455/257, 455/258, 455/302, 455/313, 455/318, 455/323, 455/324, 455/326, 455/334, 455/150.1, 455/179.1, 455/182.1, 455/315
• US Class Current: 455/150.1
• CPC Class Codes: H03D 3/007 by converting the oscillations into two quadrature related signals H03D3/245 takes precedence
• CPC Class Codes: H03D 3/009 Compensating quadrature phase or amplitude imbalances
• CPC Class Codes: H03D 7/165 at least two frequency changers being located in different paths, e.g. in two paths with carriers in quadrature combined with amplitude demodulation H03D1/2245, combined with angle demodulation H03D3/007; N-path filters H03H19/002
• CPC Class Codes: H04B 1/06 Receivers
• CPC Class Codes: H04B 1/10 Means associated with receiver for limiting or suppressing noise or interference
• CPC Class Codes: H04B 1/16 Circuits
• CPC Class Codes: H04B 1/26 for superheterodyne receivers multiple frequency-changing H03D7/16
• CPC Class Codes: H04B 1/30 for homodyne or synchrodyne receivers demodulator circuits H03D1/22
• CPC Class Codes: H04L 25/067 providing soft decisions, i.e. decisions together with an estimate of reliability H04L25/068 and H04L25/069 take precedence; sequence estimation techniques H04L25/03178

Abstract

A disclosed method tunes a signal from a channelized spectrum having a predetermined channel spacing. A signal of interest having a predetermined maximum bandwidth is mixed with a local oscillator signal, which has a frequency that is an integer multiple of the channel spacing or one-half of a channel spacing displaced from an integer multiple of the channel spacing. The local oscillator signal is selected to frequency translate the signal of interest to within a near-baseband passband whose lower edge is spaced from DC by at least about the maximum bandwidth of the signal of interest. Problems associated with 1/f noise, DC offsets, and self-mixing products are avoided or substantially diminished. Other methods and systems are also disclosed.

Claims

1. A tuner comprising a local oscillator for providing a local oscillator signal having a frequency selected from a plurality of local oscillator frequencies and a continuous-time mixer for mixing an incoming signal with the local oscillator signal so as to translate a lower high frequency spectrum of interest and an upper high frequency spectrum of interest to within a passband, improved wherein the local oscillator frequencies of the plurality are spaced such that there is substantially no redundant spectral coverage between:

an upper and lower high frequency spectrum of interest translated to the passband with a local oscillator signal having any first local oscillator frequency of the plurality; and

an upper and lower high frequency spectrum of interest translated to the passband with a local oscillator signal having any local oscillator frequency of the plurality other than the first local oscillator frequency of the plurality, wherein the passband comprises a range of frequencies passed by a low pass filter and excluding DC.

2. The tuner of claim 1 wherein the continuous-time mixer comprises continuous-time quadrature mixers for providing I and Q signals in approximate quadrature relationship.

3. The tuner of claim 2 further comprising a digital signal processing device responsive to the I and Q signals to substantially reject either the translated lower high frequency spectrum of interest or the translated upper high frequency spectrum of interest.

4. The tuner of claim 3 wherein the digital signal processing device is structured and arranged to perform complex multiplication on the non-rejected translated spectrum of interest to effect frequency translation of a signal of interest from said spectrum of interest to baseband.

5. The tuner of claim 4 wherein the digital signal processing device is structured and arranged so as to be able to correct errors between the I and Q signals.

6. The tuner of claim 1 further comprising a digital signal processing portion including first and second analog-to-digital converters in the form of delta-sigma modulators each of which samples a signal mixed by the mixer, and wherein the delta-sigma modulators are each followed by a decimating filter.

7. A method of tuning a desired signal, the method comprising:

setting a local oscillator signal to a frequency selected from a given plurality of local oscillator frequencies, mixing the desired signal with a local oscillator signal to translate a lower high frequency spectrum of interest and an upper high frequency spectrum of interest to within a passband, the passband being sized and positioned, and the local oscillator frequencies of the plurality of local oscillator frequencies being spaced sufficiently far apart, such that there is substantially no redundant spectral coverage between;

(1) an upper and a lower high frequency spectrum of interest translated to the passband with a local oscillator signal having any first local oscillator frequency of the plurality; and

(2) an upper and a lower high frequency spectrum of interest translated to the passband with a local oscillator signal having any local oscillator frequency of the plurality other than the first local oscillator frequency of the plurality, wherein the passband comprises a low pass filter and excludes DC.

8. The method of claim 7 wherein the step of mixing further comprises quadrature mixing the desired signal with the local oscillator signal, to produce I and Q signals in approximate quadrature relationship.

9. The method of claim 7 further comprising correcting errors between the I and Q signals.

10. The method of claim 7 further comprising substantially rejecting either the translated lower high frequency spectrum of interest or the translated upper high frequency spectrum of interest.

11. A tuner comprising a local oscillator for providing a local oscillator signal having a frequency selected from a plurality of local oscillator frequencies and a continuous-time mixer for mixing an incoming signal with the local oscillator signal so as to translate a lower high frequency spectrum of interest and an upper high frequency spectrum of interest to within a passband, improved wherein the local oscillator frequencies of the plurality are spaced such that there is substantially no redundant spectral coverage between:

an upper and lower high frequency spectrum of interest translated to the passband with a local oscillator signal having any first local oscillator frequency of the plurality; and

an upper and lower high frequency spectrum of interest translated to the passband with a local oscillator signal having any local oscillator frequency of the plurality other than the first local oscillator frequency of the plurality, wherein the passband comprises a low pass filter and excludes DC, and wherein each of the plurality of local oscillator frequencies are centered between different upper and lower high frequency spectrums of interest.

12. The tuner of claim 11 wherein the continuous-time mixer comprises continuous-time quadrature mixers for providing I and Q signals in approximate quadrature relationship.

13. The tuner of claim 12 further comprising a digital signal processing device responsive to the I and Q signals to substantially reject either the translated lower high frequency spectrum of interest or the translated upper high frequency spectrum of interest.

14. The tuner of claim 13 wherein the digital signal processing device is structured and arranged to perform complex multiplication on the non-rejected translated spectrum of interest to effect frequency translation of a signal of interest from said spectrum of interest to baseband.

15. The tuner of claim 14 wherein the digital signal processing device is structured and arranged so as to be able to correct errors between the I and Q signals.

16. The tuner of claim 11 further comprising a digital signal processing portion including first and second analog-to-digital converters in the form of delta-sigma modulators each of which samples a signal mixed by the mixer, and wherein the delta-sigma modulators are each followed by a decimating filter.

17. A method of tuning a desired signal, the method comprising:

setting a local oscillator signal to a frequency selected from a given plurality of local oscillator frequencies, mixing the desired signal with a local oscillator signal to translate a lower high frequency spectrum of interest and an upper high frequency spectrum of interest to within a passband, the passband being sized and positioned and the local oscillator frequencies of the plurality of local oscillator frequencies being spaced sufficiently far apart such that there is substantially no redundant spectral coverage between;

(1) an upper and a lower high frequency spectrum of interest translated to the passband with a local oscillator signal having any first local oscillator frequency of the plurality; and

(2) an upper and a lower high frequency spectrum of interest translated to the passband with a local oscillator signal having any local oscillator frequency of the plurality other than the first local oscillator frequency of the plurality, wherein the passband comprises a low pass filter and excludes DC, and wherein each of the plurality of local oscillator frequencies are centered between different upper and lower high frequency spectrums of interest.

18. The method of claim 17 wherein the step of mixing further comprises quadrature mixing the desired signal with the local oscillator signal, to produce I and Q signals in approximate quadrature relationship.

19. The method of claim 17 further comprising correcting errors between the I and Q signals.

20. The method of claim 17 further comprising substantially rejecting either the translated lower high frequency spectrum of interest or the translated upper high frequency spectrum of interest.