Wideband phase modulator

• US 8,723,613 B2
• Filed: 08/23/2011
• Issued: 05/13/2014
• Est. Priority Date: 03/11/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Sun, Bo
• Primary Examiner(s): Johnson, Ryan
• Application Number:
  US13/215,676
• Publication Number:
  US 20110304368A1
• Time in Patent Office: 994 Days
• Field of Search: 332/103, 332/117, 332/119, 332/120, 332/144, 332/145, 375/302, 375/308, 375/376, 455/110
• US Class Current: 332/103
• CPC Class Codes: H03C 3/00 Angle modulation H03C5/00, H03C7/00 take precedence
• CPC Class Codes: H03L 7/0812 and where no voltage or current controlled oscillator is used
• CPC Class Codes: H04L 27/2032 for discrete phase modulation, e.g. in which the phase of the carrier is modulated in a nominally instantaneous manner
• CPC Class Codes: H04L 27/205 in which the data are represented by the change in phase of the carrier
• CPC Class Codes: H04L 27/361 Modulation using a single or unspecified number of carriers, e.g. with separate stages of phase and amplitude modulation

Abstract

An apparatus for phase modulation includes a delay locked loop configured to generate from a reference signal a plurality of phase shifted signals, each of the phase shifted signals being locked to the reference signal and having a different phase shift from the other phase shifted signals with respect to the reference signal, and a multiplexer configured to select one of the phase shifted signals.

Claims

1. An apparatus for phase modulation, comprising:

a delay locked loop configured to generate a plurality of phase shifted signals from a reference signal, each of the phase shifted signals being locked to the reference signal and having a different phase shift from the other phase shifted signals with respect to the reference signal, wherein the reference signal is periodic, and wherein the delay locked loop comprises a delay line configured to receive the reference signal, the delay line having a delay substantially equal to the period of the reference signal; and

a selection circuit configured to output one of the phase shifted signals based on phase information, wherein the selection circuit comprises a logic circuit configured to generate a phase change direction command and a phase change magnitude command based on the phase information, wherein the selection circuit is configured to output the one of the phase shifted signals based on the phase change direction and phase change magnitude commands.

2. The apparatus of claim 1, wherein the selection circuit further comprises a shift register configured to generate a plurality of select signals based on the phase change direction command and the phase change magnitude command, wherein the selection circuit is configured to output the one of the phase shifted signals based on the plurality of select signals.

3. The apparatus of claim 1, further comprising a constellation mapper configured to generate the phase information from which the selection circuit is configured to output the one of the phase shifted signals.

4. The apparatus of claim 1 wherein the delay line comprises a plurality of delay elements connected in series, and wherein each of the phase shifted signals generated from the reference signal is provided to the selection circuit from respective outputs of the delay elements.

5. The apparatus of claim 1 wherein the delay line comprises a plurality of variable delay elements, the apparatus further comprising a phase detector configured to detect an error signal based on a difference between a phase of the reference signal and a phase of one of the phase shifted signals, wherein the delay of each of the delay elements is varied as a function of the error signal.

6. A method for phase modulation, comprising:

generating a plurality of phase shifted signals from a reference signal, wherein the phase shifted signals are locked to the reference signal, and further wherein the phase shifted signals have distinct phases with respect to the reference signal, wherein generating the plurality of select signals is based on received phase information, wherein the reference signal is periodic, and wherein the phase shifted signals are generated with a delay line configured to receive the reference signal, the delay line having a delay substantially equal to the period of the reference signal;

generating a phase change direction command based on received phase information;

generating a phase change magnitude command based on the received phase information; and

outputting a selected one of the phase shifted signals based on the phase change direction command and the phase change magnitude command.

7. An apparatus for phase modulation, comprising:

a delay locked loop configured to generate a plurality of phase shifted signals from a reference signal, each of the phase shifted signals being locked to the reference signal and having a different phase shift from the other phase shifted signals with respect to the reference signal; and

a multiplexer configured to select one of the phase shifted signals based on a phase change direction command and a phase change magnitude command.

8. The apparatus of claim 7, further comprising a logic circuit configured to generate the phase change direction command and the phase change magnitude command based on received phase information.

9. The apparatus of claim 7, further comprising a select circuit configured to generate a control signal based on the phase change direction command and the phase change magnitude command, said control signal being used by the multiplexer to select one of the phase shifted signals.

10. The apparatus of claim 9, wherein the select circuit comprises a shift register.

11. The apparatus of claim 9, wherein the select circuit comprises a linear feedback shift register (LFSR).

12. The apparatus of claim 11, wherein the linear feedback shift register (LFSR) is bidirectional.

13. A method for phase modulation, comprising:

generating a plurality of phase shifted signals from a reference signal, wherein the phase shifted signals are locked to the reference signal, and further wherein the phase shifted signals have distinct phases with respect to the reference signal; and

selecting one of the plurality of phase shifted signals based on a phase change direction command and a phase change magnitude command.

14. The method of claim 13, further comprising generating the phase change direction command and the phase change magnitude command based on received phase information.

15. An apparatus for phase modulation, comprising:

means for generating a plurality of phase shifted signals from a reference signal, each of the phase shifted signals being locked to the reference signal and having a different phase shift from the other phase shifted signals with respect to the reference signal, wherein the reference signal is periodic, and wherein the means for generating the plurality of phase shifted signals comprises means for sequentially delaying the reference signal to generate the plurality of phase shifted signals, the means for sequentially delaying having an aggregate delay equal to substantially a period of the reference signal; and

means for outputting one of the phase shifted signals based on received phase information, wherein the means for outputting the one of the phase shifted signals is configured to generate a phase change direction command and a phase change magnitude command based on the received phase information, and wherein the means for outputting the one of the phase shifted signals is configured to output the one of the phase shifted signals based on the phase change direction and phase change magnitude commands.

16. A non-transitory computer readable medium encoded with codes executable by at least one processor to:

generate a plurality of phase shifted signals from a reference signal, wherein the phase shifted signals are locked to the reference signal, and further wherein the phase shifted signals have distinct phases with respect to the reference signal, wherein the reference signal is periodic, and wherein the phase shifted signals are generated with a delay line configured to receive the reference signal, the delay line having a delay substantially equal to the period of the reference signal;

generate a phase change direction command based on received phase information;

generate a phase change magnitude command based on the received phase information; and

outputting one of the phase shifted signals based on the phase change direction command and the phase change magnitude command.

17. An apparatus for phase modulation, comprising:

means for generating a plurality of phase shifted signals from a reference signal, each of the phase shifted signals being locked to the reference signal and having a different phase shift from the other phase shifted signals with respect to the reference signal; and

means for selecting one of the phase shifted signals based on a phase change direction command and a phase change magnitude command.

18. A non-transitory computer readable medium encoded with codes executable by at least one processor to:

generate a plurality of phase shifted signals from a reference signal, wherein the phase shifted signals are locked to the reference signal, and further wherein the phase shifted signals have distinct phases with respect to the reference signal; and

select one of the plurality of phase shifted signals based on a phase change direction command and a phase change magnitude command.