Abstract
The operator chooses the new frequency. The rack keeps transmitting the full audio stream on the old carrier for a hold time that is a rack-local setting and is never transmitted. During the hold, the rack’s normal periodic beacon, at its normal rate and authenticated with its normal keyed tag, carries a retune field containing only the new frequency and the system’s key fingerprint. It carries no switch time, delay, countdown, remaining-beacon count or list of channels. A pack acts only on a beacon whose tag verifies under its stored key and whose fingerprint is its own. It stores the new frequency as pending (in RAM and in non-volatile memory), keeps playing the old carrier, and moves only when the old carrier is lost. It then retunes all of its radios together to the pending frequency. It never transmits. Re-acquisition after power-on, loss of signal or a missed retune tries, in order: the pending frequency, the last channel, the pack’s own history of channels on which it has itself received a verified beacon (cleared on re-pairing), and finally a full sweep of the tuning range in carrier-width steps. At every step a sweeping pack accepts only a beacon whose authenticated 24-bit key fingerprint is its own, so neighbouring systems are skipped. First contact is made over an infrared link from rack to pack carrying the channel, the key fingerprint and the pairing salt, at a rate above 9600 baud.
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Recommended Citation
Anonymous, "Receive-only frequency follow for a wireless audio link: an untimed authenticated retune field, carrier-loss-triggered retune of all receivers together, own-history re-acquisition and a keyed sweep", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/12132