Receiver system using analog to digital conversion at radio frequency and method

• US 6,678,512 B1
• Filed: 04/14/2000
• Issued: 01/13/2004
• Est. Priority Date: 04/14/2000
• Status: Expired due to Term

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Kolsrud, Arild, Kaminski, Walter Joseph
• Primary Examiner(s): Trost, William
• Assistant Examiner(s): Ewart, James D
• Application Number:
  US09/548,995
• Time in Patent Office: 1,369 Days
• Field of Search: 455/180.1, 455/188.1, 455/307, 455/552, 455/553, 455/323, 455/324, 455/334, 455/338-340, 375/136, 375/147, 375/335, 375/346-349, 375/316, 375/347, 375/355
• US Class Current: 455/334
• CPC Class Codes: H04B 1/28 the receiver comprising at least one semiconductor device having three or more electrodes
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes

Abstract

A receiver receives analog signals at radio frequency (RF), and the RF analog signals are converted into the digital domain. As such, the receiver does not require frequency conversion stage(s) prior to analog to digital conversion. For example, the receiver can comprise at least one antenna(s) which receives radio frequency (RF) analog signals at different frequency bands. The analog RF signals are provided to a single analog to digital (A/D) converter, and the A/D converter converts the analog RF signals at the different frequency bands into digital signals within the Nyquist bandwidth. By properly selecting the sampling rate of the A/D converter for the RF analog signals, the A/D converter can produce replicas of the different frequency bands of the analog signals in non-overlapping portions of the Nyquist bandwidth.

Claims

1. A method of processing received signals, comprising:

providing, without requiring frequency conversion or down-conversion to RF, analog signals at different RF frequency bands on a plurality of channel branches;

combining said analog signals at said different RF frequency bands on said plurality of branches; and

digitally converting said analog signals at said different RF frequency bands at a selected sampling rate to produce digital signals at different frequency bands,

said sampling rate selected so that said different frequency bands of said analog signals fold back to substantially non-overlapping portions of a Nyquist zone as said analog signals are digitally converted.

2. The method of claim 1 further comprising:

receiving said analog signals on at least two antennas.

3. The method of claim 2, wherein said providing further includes:

using a first antenna to provide analog signals of a first frequency band on a first channel branch; and

using a second antenna to provide analog signals of a second frequency band on a second channel branch.

4. The method of claim 1, wherein said providing further includes:

filtering on each channel branch said analog signals to provide analog signals having a frequency band corresponding to said channel branch.

5. The method of claim 1, wherein said providing further includes:

receiving analog signals from at least one antenna; and

selectively producing, on each channel branch, analog signals having a frequency band corresponding to said channel branch.

6. The method of claim 1, wherein said digitally converting of said analog signals at said different RF frequency bands is performed at a sampling rate selected so that a signal bandwidth of said combined analog signals and a mirror image of said signal bandwidth periodically repeats at frequency intervals corresponding to said selected sampling rate.

10. The method of claim 1, wherein said digitally converting of said analog signals at said different RF frequency bands is performed at a sampling rate selected so that said different RF frequency bands fold back to substantially non-overlapping portions of a Nyquist zone as said analog signals are digitally converted.

11. The method of claim 10, wherein said non-overlapping portions of said Nyquist zone represent the Nyquist bandwidth provided by said digitally converting to reproduce said RF analog signals in the digital domain.

12. The method of claim 10, wherein said selected sampling rate is at least twice a signal bandwidth of said combined analog signals, so that said signal bandwidth rotates periodically about itself at frequency multiples of one-half said selected sampling frequency back to a first Nyquist zone in the digital domain from about 0 Hz to said selected sampling rate.

13. The method of claim 12, wherein said selected sampling rate is at least twice a highest frequency component of said signal bandwidth so that information within said analog signals carried by said signal bandwidth are reproduced in the digital domain.

14. The method of claim 10, wherein said selected sampling rate is at least twice the signal bandwidth of said combined analog signals.

7. A receiver, comprising:

at least one antenna for receiving analog signals in different radio frequency (RF) frequency bands;

a channel branch arrangement connected to said at least one antenna for receiving analog signals and providing, without requiring frequency conversion or down-conversion to RF, analog signals onto a plurality of channel branches at different RF bands;

a combining arrangement connected to said plurality of channel branches for combining said analog signals on said plurality of channel branches; and

an analog to digital converter configured to receive and digitally convert said analog signals at said different RF bands to produce digital signals at different frequencies.

8. The receiver of claim 7, including at least two antennas for providing said channel branch arrangement with said analog signals.

9. The receiver of claim 8, wherein said channel branch arrangement is configured to provide, on a first channel branch, analog signals from a first antenna of a first frequency band, and to provide, on a second channel branch, analog signals from a second antenna of a second frequency band.

15. The receiver of claim 7, wherein said analog to digital converter digitally converts said analog signals at said different RF frequency bands at a sampling rate selected so that said different RF frequency bands fold back to substantially non-overlapping portions of a Nyquist zone as said analog signals are digitally converted.

16. The receiver of claim 15, wherein said non-overlapping portions of said Nyquist zone represent the Nyquist bandwidth provided by said digitally converting to reproduce said RF analog signals in the digital domain.

17. The receiver of claim 15, wherein said selected sampling rate is at least twice a signal bandwidth of said combined analog signals, so that said signal bandwidth rotates periodically about itself at frequency multiples of one-half said selected sampling frequency back to a first Nyquist zone in the digital domain from about 0 Hz to said selected sampling rate.

18. The receiver of claim 17, wherein said selected sampling rate is at least twice a highest frequency component of said signal bandwidth so that information within said analog signals carried by said signal bandwidth are reproduced in the digital domain.

19. The receiver of claim 15, wherein said selected sampling rate is at least twice the signal bandwidth of said combined analog signals.

20. The receiver of claim 7, wherein said analog to digital converter digitally converts said analog signals at said different RF frequency bands at a sampling rate selected so that a signal bandwidth of said combined analog signals and a mirror image of said signal bandwidth periodically repeats at frequency intervals corresponding to said selected sampling rate.