Patent ID: 8718193

Claim:
A signal receiver, comprising: (a) a receiver module configured to receive an encoded signal from an in vivo transmitter in a low signal to noise ratio (SNR) environment, the receiver module comprising: a first demodulator to receive the encoded signal and to produce a filtered complex baseband signal; a carrier frequency detector to receive the filtered complex baseband signal and generate an estimated carrier offset frequency; a second demodulator to receive the complex baseband signal and the estimated carrier offset frequency and to produce a demodulated encoded signal; and (b) a decoder module coupled to the receiver module to receive the demodulated encoded signal, the decoder module configured to decode the demodulated encoded signal with substantially no error; wherein the signal receiver is sized to be stably associated with a living subject in a manner that does not substantially impact movement of the living subject, wherein the first demodulator comprises: a first mixer; a direct digital synthesizer coupled to the first mixer to produce a nominal carrier frequency, wherein the received encoded signal is mixed by the mixer with the nominal carrier frequency to produce the complex baseband signal; and a first low pass filter coupled to the first mixer to filter the complex baseband signal.