Methods of receiving communications signals including a plurality of digital filters having different bandwidths and related receivers

• US 6,768,441 B2
• Filed: 08/20/2002
• Issued: 07/27/2004
• Est. Priority Date: 08/20/2002
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Singvall, Jakob, Stenstrom, Niklas
• Primary Examiner(s): Tohar, Michael
• Assistant Examiner(s): Nguyen, Linh V
• Application Number:
  US10/224,303
• Publication Number:
  US 20040036637A1
• Time in Patent Office: 707 Days
• Field of Search: 341/110, 341/118, 341/143, 341/144, 341/155, 341/141, 375/141, 375/211, 375/247, 375/316, 375/346, 375/340, 375/327
• US Class Current: 341/155
• CPC Class Codes: H03G 3/3052 in bandpass amplifiers (H.F. or I.F.) or in frequency-changers used in a (super)heterodyne receiver H03G3/32, H03G3/34 take precedence

Abstract

Methods of receiving communications signals can include generating a received analog signal including energy corresponding to communications transmitted from a remote transmitter, and performing an analog-to-digital conversion of the received analog signal to provide a received digital signal. The received digital signal can be digitally filtered using a first digital filter having a first bandwidth to provide a first filtered digital signal, and the first filtered digital signal can be processed to provide an estimate of the communications transmitted from the remote transmitter. The received digital signal can be digitally filtered using a second digital filter having a second bandwidth to provide a second filtered digital signal wherein the second bandwidth is greater than the first bandwidth, and a signal characteristic of the second filtered digital signal can be measured. Related receivers are also discussed.

Claims

1. A method of receiving communications signals, the method comprising:

generating a received analog signal including energy corresponding to communications transmitted from a remote transmitter;

performing an analog-to-digital conversion of the received analog signal to provide a received digital signal;

digitally filtering the received digital signal using a first digital filter having a first bandwidth to provide a first filtered digital signal;

processing the first filtered digital signal to provide an estimate of the communications transmitted from the remote transmitter;

digitally filtering the received digital signal using a second digital filter having a second bandwidth to provide a second filtered digital signal wherein the second bandwidth is greater than the first bandwidth; and

measuring a signal characteristic of the second filtered digital signal.

2. A method according to claim 1 further comprising:

adjusting a gain of the received analog signal based on the measured signal characteristic of the second filtered digital signal.

3. A method according to claim 1 further comprising:

adjusting the first bandwidth of the first digital filter based on the measured signal characteristic of the second filtered digital signal.

4. A method according to claim 1 wherein processing the first filtered digital signal comprises performing a whitening filter function, the method further comprising:

adjusting operation of the whitening filter function based on the measured signal characteristic of the second filtered digital signal.

5. A method according to claim 1 further comprising:

digitally filtering the received digital signal using a third digital filter having a third bandwidth to provide a third filtered digital signal wherein the third bandwidth is greater than the second bandwidth; and

measuring a signal characteristic of the third filtered digital signal.

6. A method according to claim 1 wherein each of the first and second digital filters is selected from the group consisting of a finite impulse response filter, an infinite impulse response filter, a cascaded integrator-comb filter, and/or a realization filter.

7. A method according to claim 1 wherein each of the first and second digital filters comprises a cascaded integrator-comb filter.

8. A method according to claim 1 wherein the energy corresponding to the communications transmitted from the remote transmitter is transmitted over a communications channel within the first bandwidth.

9. A method according to claim 1 further comprising:

generating speech responsive to the estimate of the communications transmitted from the remote transmitter.

10. A method according to claim 1 further comprising:

generating a digital data stream responsive to the estimate of the communications transmitted from the remote transmitter.

11. A method according to claim 1 wherein the received analog signal comprises a received analog radio signal.

12. A method according to claim 1 wherein measuring a signal characteristic comprises measuring a signal strength of the second filtered digital signal.

13. A method according to claim 1 wherein measuring a signal characteristic comprises measuring adjacent channel interference.

14. A method according to claim 1 wherein the first bandwidth of the first digital filter is included within the second bandwidth of the second digital filter.

15. A method according to claim 1 wherein the first and second digital filters digitally filter the same received digital signal.

16. A receiver according to claim 1 wherein the first and second digital filters digitally filter the same received digital signal.

39. A receiver according to claim 14 wherein measuring a signal characteristic comprises measuring adjacent channel interference.

40. A method according to claim 14 wherein the first and second bandwidths have a same center frequency.

17. A receiver comprising:

a receiver configured to generate a received analog signal including energy corresponding to communications transmitted from a remote transmitter;

an analog-to-digital converter configured to convert of the received analog signal to provide a received digital signal;

a first digital filter having a first bandwidth and configured to digitally filter the received digital signal to provide a first filtered digital signal;

a digital signal processor configured to process the first filtered digital signal to provide an estimate of the communications transmitted from the remote transmitter;

a second digital filter having a second bandwidth and configured to digitally filter the received digital signal to provide a second filtered digital signal wherein the second bandwidth is greater than the first bandwidth; and

a characterization circuit configured to measure a signal characteristic of the second filtered digital signal.

18. A receiver according to claim 17 comprising:

an automatic gain control circuit configured to adjust a gain of the received analog signal based on the measured signal characteristic of the second filtered digital signal.

19. A receiver according to claim 17 wherein the first bandwidth of the first digital filter is adjusted based on the measured signal characteristic of the second filtered digital signal.

20. A receiver according to claim 17 wherein the digital signal processor is further configured to perform a whitening filter function, wherein the digital signal processor is further configured to adjust operation of the whitening filter function based on the measured signal characteristic of the second filtered digital signal.

21. A receiver according to claim 17 further comprising:

a third digital filter having a third bandwidth and configured to digitally filter the received digital signal to provide a third filtered digital signal wherein the third bandwidth is greater than the second bandwidth; and

a second characterization circuit configured to measure a signal characteristic of the third filtered digital signal.

22. A receiver according to claim 17 each of the first and second digital filters is selected from the group consisting of a finite impulse response filter, an infinite impulse response filter, a cascaded integrator-comb filter, and/or a realization filter.

23. A receiver according to claim 17 wherein each of the first and second digital filters comprises a cascaded integrator-comb filter.

24. A receiver according to claim 17 wherein the energy corresponding to the communications transmitted from the remote transmitter is transmitted over a communications channel within the first bandwidth.

25. A receiver according to claim 17 measuring a signal characteristic comprises measuring a signal strength of the second filtered digital signal.

26. A receiver according to claim 17 wherein measuring a signal characteristic comprises measuring adjacent channel interference.

27. A receiver according to claim 17 wherein the first bandwidth of the first digital filter is included within the second bandwidth of the second digital filter.

28. A receiver according to claim 27 wherein the first and second bandwidths have a same center frequency.

29. A receiver according to claim 17 wherein the first and second digital filters digitally filter the same received digital signal.

30. A receiver of receiving communications signals, the receiver comprising:

means for generating a received analog signal including energy corresponding to communications transmitted from a remote transmitter;

means for performing an analog-to-digital conversion of the received analog signal to provide a received digital signal;

means for digitally filtering the received digital signal using a first digital filter having a first bandwidth to provide a first filtered digital signal;

means for processing the first filtered digital signal to provide an estimate of the communications transmitted from the remote transmitter;

means for digitally filtering the received digital signal using a second digital filter having a second bandwidth to provide a second filtered digital signal wherein the second bandwidth is greater than the first bandwidth; and

measuring a signal characteristic of the second filtered digital signal.

31. A receiver according to claim 30 further comprising:

means for adjusting a gain of the received analog signal based on the measured signal strength of the second filtered digital signal.

32. A receiver according to claim 30 further comprising:

means for adjusting the first bandwidth of the first digital filter based on the measured signal strength of the second filtered digital signal.

33. A receiver according to claim 30 wherein processing the first filtered digital signal comprises performing a whitening filter function, the receiver further comprising:

means for adjusting operation of the whitening filter function based on the measured signal strength of the second filtered digital signal.

35. A receiver according to claim 30 wherein each of the first and second digital filters is selected from the group consisting of a finite impulse response filter, an infinite impulse response filter, a cascaded integrator-comb filter, and/or a realization filter.

36. A receiver according to claim 30 wherein each of the first and second digital filters comprises a cascaded integrator-comb filter.

37. A receiver according to claim 30 wherein the energy corresponding to the communications transmitted from the remote transmitter is transmitted over a communications channel within the first bandwidth.

38. A receiver according to claim 30 wherein measuring a signal characteristic comprises measuring a signal strength of the second filtered digital signal.

41. A receiver according to claim 30 wherein the first bandwidth of the first digital filter is included within the second bandwidth of the second digital filter.

42. A receiver according to claim 41 wherein the first and second bandwidths have a same center frequency.

34. A receiver according to claim further comprising:

means for digitally filtering the received digital signal using a third digital filter having a third bandwidth to provide a third filtered digital signal wherein the third bandwidth is greater than the second bandwidth; and

means for measuring a signal strength of the third filtered digital signal.