Abstract: A page scanning device configured to generate a sequence mask for an expected frequency hopping sequence, select a first tone among a plurality of detected tones, first determine whether the first tone is included within an expected hop sequence, generate a first tone template in response to determining that the first tone is included within the expected hop sequence, align the first tone template with the plurality of detected tones based on the first tone, second determine whether the first tone template matches the plurality of detected tones, and detect a valid frequency hopping sequence in response to determining that the first tone template matches the plurality of detected tones.

Abstract: There is described a number of encoders for encoding a data signal within an audio signal. In some of the encoders, the audio signal is separated into a tonal part and a residual part, and the data signal is shaped based on the residual part. In other encoders, the data signal is separated into a tonal part and a residual part, and the data signal is combined with the audio signal independence upon the residual part. In other encoders, the rate at which the data is encoded within the audio signal is varied in dependence upon the audio signal. There are also described various decoders associated with the described encoders.