Method and apparatus for calibration of a band-pass filter and squelch detector in a frequency-shift keying transceiver
AssigneeNXP B.V.
InventorsSiamak DELSHADPOUR, Ahmad YAZDI, Xueyang GENG
Life of this patent
Estimating the term…
Abstract
Various embodiments relate to a method for calibration of a center frequency of a BPF in an FSK transceiver, the method including the steps of filtering a carrier frequency signal by the BPF to produce a filtered signal, detecting, by a phase-frequency detector (“PFD”), a difference in phase between the carrier frequency signal and the filtered signal from the BPF, sweeping a calibration code of the BPF, detecting a transition in the sign of the phase difference and capturing a calibration code associated with the transition in the sign of the phase difference for calibration of the BPF.
Claims23
A method for calibration of a center frequency of a band-pass filter (“BPF”) in an frequency shift keying (“FSK”) transceiver, the method comprising the steps of:
- filtering a carrier frequency signal by the BPF to produce a filtered signal;
- detecting, by a phase-frequency detector (“PFD”), a difference in phase between the carrier frequency signal and the filtered signal from the BPF;
- sweeping a calibration code of the BPF;
- detecting a transition in the sign of the phase difference;
- and
- capturing a calibration code associated with the transition in the sign of the phase difference for calibration of the BPF.
The method for calibration of a center frequency of a BPF in a FSK transceiver, the method further comprising:
- receiving, by a comparator, a signal from the BPF;
- and
- selecting, by a multiplexer, to receive a carrier frequency signal and transmitting the carrier frequency signal to a phase-frequency detector (“PFD”).
A frequency shift keying (“FSK”) transceiver, the FSK transceiver comprising:
- a BPF configured to:
- filter a carrier frequency signal to produce a filtered signal;
- sweep a calibration code;
- detect a transition in the sign of the phase difference;
- and
- capture a calibration code associated with the transition in the sign of the phase difference for calibration of the BPF;
- and
- a phase-frequency detector (“PFD”) configured to detect a difference in phase between the carrier frequency signal and the filtered signal from the BPF.
A FSK transceiver, the FSK transceiver comprising:
- a squelch detector configured to:
- receive the squelch detector threshold;
- receive a signal from the BPF;
- sweep the squelch detector threshold from a maximum value towards a minimum value;
- and
- compare the squelch detector threshold to the signal from the BPF;
- and
- a digital controller configured to capture a calibration code for the squelch detector threshold when the signal from the BPF exceeds the squelch detector threshold.
Dependencies are inferred from the claim text.