Efficient handling of clock offset in spread spectrum decoders

A method comprising:

• at a Doppler correlator bank including:
• one or more first butterfly elements coupled between an input node and an intermediate node, the input node configured to receive samples of a signal sampled based on a frequency;
• and sets of one or more second butterfly elements, the sets of one or more second butterfly elements coupled in parallel with each other between the intermediate node and respective output nodes and configured with respective phase rotations that vary across the sets of one or more second butterfly elements:
• by the one or more first butterfly elements, performing sub-correlations on the samples to produce an intermediate correlation result;
• and
• by the sets of one or more second butterfly elements, performing respective correlations in parallel on, and applying the respective phase rotations to, the intermediate correlation result, to produce respective correlation results at the respective output nodes and centered on respective frequency offsets from the frequency that vary across the respective correlation results based on the respective phase rotations.

A non-transitory computer readable medium encoded with instruction that, when executed by a processor, cause the processor to perform operations associated with a Doppler correlator bank that includes:

• one or more first butterfly elements coupled between an input node and an intermediate node, the input node configured to receive samples of a signal sampled based on a frequency;
• and sets of one or more second butterfly elements, the sets of one or more second butterfly elements coupled in parallel with each other between the intermediate node and respective output nodes and configured with respective phase rotations that vary across the sets of one or more second butterfly elements, the operations including:
• performing, by the one or more first butterfly elements, sub-correlations on the samples to produce an intermediate correlation result;
• and
• performing, by the sets of one or more second butterfly elements, respective correlations in parallel on, and applying the respective phase rotations to, the intermediate correlation result, to produce respective correlation results at the respective output nodes and centered on respective frequency offsets from the frequency that vary across the respective correlation results based on the respective phase rotations.