A method of demodulating a signal that is phase modulated to convey R chips having phase transitions between adjacent ones of the R chips to represent chip states, and an overlay symbol spanning the R chips, wherein R>1, and wherein the phase transitions are rotated in a same direction according to an overlay symbol state, comprises: first processing the signal including: accumulating a respective phase of each chip into a respective first chip magnitude, to produce R first chip magnitudes; and accumulating the R first chip magnitudes to produce a first magnitude; second processing the signal including: accumulating a respective phase of each chip into a respective second chip magnitude, to produce R second chip magnitudes; and accumulating the R second chip magnitudes to produce a second magnitude; and determining the overlay symbol state based on the first magnitude and the second magnitude.

A wireless communications device may include a wireless receiver, and an adaptive demodulator coupled to the wireless receiver. The adaptive demodulator is configured to apply first and second bandpass filters to amplitude information of a received signal at first and second frequency bands, respectively, and classify the received signal as one of a PSK modulation type, a second PSK modulation type, and a third FSK modulation type based upon whether a tone exists in the amplitude information of the received signal in one or more of the first and second frequency bands. The adaptive demodulator is configured to adjust a demodulating parameter based upon a classified modulation type of the received signal.

An apparatus, and related method, relates generally to viable bandwidth filtering. In such an apparatus, an analysis filter bank has path filters associated with different bandwidths and is configured for filtering and transforming an input signal having a first bandwidth into a first interleaved output. A mask is coupled to the analysis filter bank and configured for masking at least one narrowband time signal of the first interleaved output. A synthesis filter bank is coupled to the mask. The synthesis filter bank is configured for transforming and filtering the masked first interleaved output to generate a second interleaved output for constructing an output signal having a second bandwidth. The second bandwidth is different than the first bandwidth for the variable bandwidth filtering.

A receiver includes a receiver circuit to receive a pulse width modulated signal, which assumes a first signal level, a second signal level and an intermediate signal level between the first signal level and the second signal level. The receiver further includes a quantization circuit to determine a value encoded in the signal based on an intermediate time period between a first transition and an intermediate transition and based on a main time period between the first transition and a second transition. The first transition comprises the first signal level, wherein the intermediate transition includes the intermediate signal level. The second transition includes the second signal level.

A receiver includes a receiver circuit to receive a pulse width modulated signal, which assumes a first signal level, a second signal level and an intermediate signal level between the first signal level and the second signal level. The receiver further includes a quantization circuit to determine a value encoded in the signal based on an intermediate time period between a first transition and an intermediate transition and based on a main time period between the first transition and a second transition. The first transition comprises the first signal level, wherein the intermediate transition includes the intermediate signal level. The second transition includes the second signal level.

In described examples, a method of inductive coupled communications includes providing a first resonant tank (first tank) and a second resonant tank (second tank) tuned to essentially the same resonant frequency, each having antenna coils and switches positioned for changing a Q and a bandwidth of their tank. The antenna coils are separated by a distance that provides near-field communications. The first tank is driven to for generating induced oscillations to transmit a predetermined number of carrier frequency cycles providing data. After the predetermined number of cycles, a switch is activated for widening the bandwidth of the first tank. Responsive to the oscillations in the first tank, the second tank begins induced oscillations. Upon detecting a bit associated with the induced oscillations, a switch is activated for widening the bandwidth of the second tank and a receiver circuit receiving an output of the second tank is reset.