FM pulse shaping
AssigneeQuintic Holdings
InventorJohn B. Groe
Life of this patent
Estimating the term…
Abstract
Apparatus and methods for improving the spectral performance of a polar modulator are described. A composite FM signal component of a composite polar transmit signal may be processed by monitoring the FM signal to detect a transient burst component, and, responsive to detection of a transient burst, generating a spectrally friendly replacement signal component that may be combined with the FM signal to improve spectral performance of the composite signal. In addition, an associated AM component of the composite transmit signal may be filtered to further improve spectral performance.
Claims29
A method of improving the spectral performance of a polar transmitter, comprising:
- receiving an FM signal, said FM signal being a component of a composite transmit signal;
- detecting a transient burst signal component of the FM signal based on a set of detection rules;
- generating, responsive to said detecting, a replacement pulse signal component;
- and
- replacing a sequence of one or more samples of said FM signal with said replacement pulse signal component to generate an adjusted FM signal based on replacing rules;
- wherein said replacement pulse signal component is disposed to improve the spectral characteristics of the adjusted FM signal.
An apparatus for modifying an FM signal in a polar transmitter, the apparatus comprising:
- a detection module configured to monitor said FM signal and identify when a parameter of said FM signal exceeds a threshold value;
- a sample replacement module coupled to said detection module, the sample replacement module configured to determine, based at least in part on said identifying, a sequence of one or more samples of said FM signal to be replaced;
- an energy measurement module coupled to said sample replacement module, the energy measurement module configured to determine a replacement signal energy metric based on said sequence of one or more samples of said FM signal;
- a replacement signal generation module coupled to said energy measurement module, the
- replacement signal generation module configured to generate a replacement signal sample sequence based at least in part on said replacement signal energy metric;
- and
- a signal modification module coupled to said FM signal, said sample replacement module and said replacement signal generation module, the signal modification module configured to replace said sequence of one or more samples of said FM signal with said replacement signal sample sequence to generate an adjusted FM signal.
A polar modulator comprising:
- a phase-locked loop;
- a variable gain amplifier coupled to an output of the phase-locked loop;
- and
- an FM signal adjustment circuit coupled to the phase-locked loop, said FM signal adjustment circuit comprising:
- a detection module configured to monitor said FM signal and identify when a parameter of said FM signal exceeds a threshold value;
- a sample replacement module coupled to said detection module, the sample replacement module configured to determine, based at least in part on said identifying, a sequence of one or more samples of said FM signal to be replaced;
- an energy measurement module coupled to said sample replacement module, the energy measurement module configured to determine a replacement signal energy metric based on said sequence of one or more samples of said FM signal;
- a replacement signal generation module coupled to said energy measurement module, the replacement signal generation module configured to generate a replacement signal sample sequence based at least in part on said replacement signal energy metric;
- and
- a signal modification module coupled to said FM signal, said sample replacement module and said replacement signal generation module, the signal modification module configured to replace said sequence of one or more samples of said FM signal with said replacement signal sample sequence to generate an adjusted FM signal.
Dependencies are inferred from the claim text.