Frame synch detection with rate adaptation

A method of operating a wireless device that comprises a receiver, a data resampler circuit coupled to the receiver, and a correlation circuit coupled to the data resampler circuit, wherein the method of operating the wireless device comprises:

• receiving wirelessly, by the receiver, a packet over a channel at a first frequency;
• generating, by the receiver, a sampled stream of data from the packet at a first sample rate corresponding to the first frequency;
• determining, by the data resampler circuit using a fractional conversion ratio between the first sample rate and a crystal oscillator (XO)-integer-divided sample rate, a plurality of re-timer values comprising differences between pulses of a pseudo clock corresponding to the XO-integer-divided sample rate and closest corresponding pulses of a clock corresponding to the first sample rate;
• re-sampling, by the data resampler circuit, data values of the sampled stream of data associated with locations of the plurality of re-timer values;
• and
• matching, by the correlation circuit using the re-sampled data values, the pseudo clock, and the plurality of re-timer values, an expected data pattern to a corresponding data pattern detected in a frame delimiter of the packet.

A system comprising:

• a first wireless device adapted to gain access to a secured enclosure by transmitting data comprising a frame delimiter;
• and
• a second wireless device located within the secured enclosure, the second wireless device comprising:
• a receiver to wirelessly receive a packet over a channel at a first frequency and generate a sampled stream of data from the packet at a first sample rate corresponding to the first frequency;
• a data resampler circuit coupled to the receiver, the data resampler circuit comprising:
• a re-timer engine to determine, using a fractional rate between the first sample rate and a crystal oscillator (XO)-integer-divided sample rate, a plurality of re-timer values comprising differences between pulses of a pseudo clock corresponding to the XO-integer-divided sample rate and closest corresponding pulses of a clock corresponding to the first sample rate;
• and
• a time shifting circuit to re-sample data values of the sampled stream of data associated with locations of the plurality of re-timer values;
• and
• a correlation circuit coupled to the data resampler circuit, the correlation circuit to use the re-sampled data values, the pseudo clock, and the plurality of re-timer values to match an expected data pattern to a corresponding data pattern detected in a frame delimiter of the packet.