A change in a detection voltage due to the temperature is suppressed. A detector circuit includes: a first rectification element having an anode to which an input signal is inputted; a second rectification element having a cathode connected with a cathode of the first rectification element and having an anode connected to an output terminal; and a current mirror circuit for supplying a current to the first rectification element, and for supplying a current-mirror current of the current to the second rectification element.

Systems and methods for a non-data-aided (NDA) approach to advanced OFDM timing are provided. This approach allows for accurate OFDM symbol timing and synchronization by avoiding inter-symbol interference (ISI) in multipath environments where an earliest arriving signal may not be the strongest signal. The NDA approach may rely on generating and applying a bias correction to a combined correlation result of the multi-path signals.

A transceiver that allows dynamic high-pass filter (HPF) cut-off frequency adjustment may include a mixer circuit to mix a local oscillator (LO) signal with a receive (RX) signal received from a transmitter to generate a baseband signal. The transceiver may further include a high-pass filter (HPF) having an adjustable cut-off frequency that is used to reduce a DC offset of the baseband signal. A control circuit can dynamically control components of the HPF to set the adjustable cut-off frequency at a first frequency during a first time period and at a second frequency during a second time period.

A communication device for receiving an interrogation signal at a first carrier frequency and for transmitting a response signal at a second carrier frequency is disclosed. The interrogation signal comprises the first carrier frequency modulated at the second carrier frequency. The communication device includes a sensor coupled to a demodulator. The sensor receives a low frequency input used to further modulate the interrogation signal. The demodulator demodulates the low frequency input from the first carrier frequency to thereby generate the response signal comprising the second carrier frequency and the low frequency input. The demodulator preferably includes a pyroelectric demodulator, a piezoelectric demodulator, or a detector diode. The demodulator preferably has a frequency response less than the first carrier frequency but greater than the second carrier frequency.

A communication device for receiving an interrogation signal at a first carrier frequency and for transmitting a response signal at a second carrier frequency is disclosed. The interrogation signal comprises the first carrier frequency modulated at the second carrier frequency. The communication device includes a sensor coupled to a demodulator. The sensor receives a low frequency input used to further modulate the interrogation signal. The demodulator demodulates the low frequency input from the first carrier frequency to thereby generate the response signal comprising the second carrier frequency and the low frequency input. The demodulator preferably includes a pyroelectric demodulator, a piezoelectric demodulator, or a detector diode. The demodulator preferably has a frequency response less than the first carrier frequency but greater than the second carrier frequency.

A receiving system of the present disclosure includes: a plurality of demodulators; an add-on generating one stream based on an output from each of the demodulators; a selector selecting and outputting one among an output from one of the demodulators, namely the demodulator, and the one stream from the add-on; and a back-end processor generating an output for a display based on an output from the selector and the other demodulators, namely the demodulators. The selector selects an output from the demodulator in a single channel transmission mode, and selects the stream from the add-on in a multiple channel transmission mode.

The present invention relates to a method and apparatus for channel estimation between a transmitter and a receiver in a wireless communications system. In one arrangement, the method comprises: receiving at the receiver a first sequence of bits representing a first sequence of coded symbols transmitted over the communications channel; decoding the first sequence of coded symbols using maximum-likelihood based decoding including: generating traceback outcomes by tracing backwards the first sequence of bits through a maximum-likelihood based traceback path, the traceback outcomes including a first portion associated with a first traceback depth and a second portion associated with a second traceback depth that is deeper than the first traceback depth; generating a channel estimate of the communications channel based on the first portion of the traceback outcomes; and generating an estimate of at least some information bits coded in the first sequence of coded symbols based on the second portion of the traceback outcomes.

A transceiver device for receiving an interrogation signal at a first carrier frequency and for transmitting a response signal at a second carrier frequency is disclosed. The interrogation signal comprises the first carrier frequency modulated at the second carrier frequency. The communication device includes a sensor coupled to a demodulator. The sensor receives a low frequency input used to further modulate the interrogation signal. The demodulator demodulates the low frequency input from the first carrier frequency to thereby generate the response signal comprising the second carrier frequency and the low frequency input. The demodulator preferably includes a pyroelectric demodulator, a piezoelectric demodulator, or a detector diode. The demodulator preferably has a frequency response less than the first carrier frequency but greater than the second carrier frequency.

A method for transmitting data by using a power line. The method includes: setting i=1 and j=1; receiving an i-th zero crossing signal at a time point ti, and determining, based on the i-th zero crossing signal, a start time when synchronization signals of a j-th data packet are transmitted, the start time when the synchronization signals of the j-th data packet are transmitted being ti+t; transmitting the synchronization signals of the j-th data packet at the start time when the synchronization signals of the j-th data packet are transmitted; transmitting data signals of the j-th data packet in sequence; and determining whether j is equal to M; when j is not equal to M, continuing a data transmission; and when j is equal to M, ending the data transmission, M being a number of data packets into which data to be transmitted is divided.

An RFID receiver (1) comprises an antenna (11) configured to receive a radio signal (20) from an RFID transmitter (2) and to generate an electrical signal (110) from the radio signal (20) received from the RFID transmitter (2). A decoder circuit (10) is connected to the antenna (11) and configured to extract from the electrical signal (110) generated by the antenna (11) data bits encoded in the electrical signal (110). The decoder circuit (10) comprises an analog-to-digital converter (12) connected directly to the antenna (11) and configured to generate a digital input signal (13) from the electrical signal (110) generated by the antenna (11). A bit extractor (14) is connected to the analog-to-digital converter (12) and configured to extract the data bits from the digital input (13) signal generated by the analog-to-digital converter (12).