Radio receiver having direct DC offset compensation

A method for direct current (DC) offset compensation in a frequency modulated (FM) radio receiver, the method comprises:

• demodulating a low intermediate frequency (IF) signal to produce demodulated data;
• determining DC offset of the demodulated data;
• determining a local oscillation adjustment value based on the DC offset;
• and
• adjusting frequency of a local oscillation by the local oscillation adjustment value.

A self-correcting clocking module for use in a data recovery circuit, the self-correcting clock module comprises:

• reference oscillation source to produce a reference oscillation;
• phase and frequency detection module operably coupled to produce a difference signal based on at least one of:
• phase difference and frequency difference between the reference oscillation and a feedback oscillation;
• charge pump module operably coupled to produce a charge up or charge down signal from the difference signal;
• low pass filter operably coupled to filter the charge up or charge down signal to produce a filtered charge up or charge down signal;
• voltage controlled oscillator operably coupled to produce a recovery clock based on the filtered charge up or charge down signal;
• and
• programmable feedback module operably coupled to produce the feedback oscillation by dividing the recovery clock by a divider value, wherein the divider value is in accordance with a predetermined clock value and a fractional adjustment value that is based on direct current (DC) offset of recover ed data.

A method for self-correcting clocking module for use in a data recovery circuit, the method comprises:

• producing a reference oscillation;
• producing a difference signal based on at least one of:
• phase difference and frequency difference between the reference oscillation and a feedback oscillation;
• producing a charge up or charge down signal from the difference signal;
• low pass filtering the charge up or charge down signal to produce a filtered charge up or charge down signal;
• producing a recovery clock based on the filtered charge up or charge down signal;
• and
• producing the feedback oscillation by dividing the recovery clock by a divider value, wherein the divider value is in accordance with a predetermined clock value and a fractional adjustment value that is based on direct current (DC) offset of recovered data.

An apparatus for direct current (DC) offset compensation in a frequency modulated (FM) radio receiver, the apparatus comprises:

• processing module;
• and
• memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to:
• demodulate a low intermediate frequency (IF) signal to produce demodulated data;
• determine DC offset of the demodulated data;
• determine a local oscillation adjustment value based on the DC offset;
• and
• adjust frequency of a local oscillation by the local oscillation adjustment value.

A self-correcting clock module for use in a data recovery circuit, the self-correcting clock module comprises:

• processing module;
• and
• memory operably coupled to the processing module, wherein the memory includes operational instructions that cause the processing module to:
• produce a reference oscillation;
• produce a difference signal based on at least one of:
• phase difference and frequency difference between the reference oscillation and a feedback oscillation;
• produce a charge up or charge down signal from the difference signal;
• low pass filter the charge up or charge down signal to produce a filtered charge up or charge down signal;
• produce a recovery clock based on the filtered charge up or charge down signal;
• and
• produce the feedback oscillation by dividing the recovery clock by a divider value, wherein the divider value is in accordance with a predetermined clock value and a fractional adjustment value that is based on direct current (DC) offset of recovered data.