443 results about "Signal envelope" patented technology

A transceiver comprises an amplifying circuit for amplifying an input signal to produce an output signal. A power supply is operable for varying the level of power supplied to the amplifying circuit in response to variation of an input signal envelope directed to the power supply. A processing circuit is operable for digitally detecting the input signal envelope to provide variation of the power supply level. The processing circuit is further operable for digitally delaying the digital input signal envelope to time align the power supply level with the input signal.

A radio frequency amplification stage including an amplifier for receiving an input signal to be amplified and a power supply voltage; and a power supply voltage stage for supplying said power supply voltage, including a circuit for providing a reference signal representing the envelope of the input signal; a circuit for selecting one of a plurality of supply voltage levels in dependence on the reference signal; and a circuit for generating an adjusted selected power supply voltage, including an ac amplifier for amplifying a difference between the reference signal and one of the selected supply voltage level or the adjusted selected supply voltage level, and a summer for summing the amplified difference with the selected supply voltage to thereby generate the adjusted supply voltage.

A transceiver comprises an amplifying circuit for amplifying an input signal to produce an output signal. A power supply is operable for varying the level of power supplied to the amplifying circuit in response to variation of an input signal envelope directed to the power supply. A processing circuit is operable for digitally detecting the input signal envelope to provide variation of the power supply level. The processing circuit is further operable for digitally delaying the digital input signal envelope to time align the power supply level with the input signal.

The invention relates to the offset-modulation orthogonal frequency division multiplexing and multicast communication with a cyclic prefix, which comprises a transmitted signal producing method at the transmitting end and a received signal processing method at the receiving end. The method comprises the following steps of: carrying out the generalized discrete Fourier transform on real value digital baseband modulation signs at the transmitting end to obtain frequency-domain signals; carrying out the conjugate symmetrical expansion, the frequency-domain filtering and the sub-carrier mapping on the frequency-domain signals; carrying out the inverse fast Fourier transform on the frequency-domain signals obtained after the sub-carrier mapping; inserting the cyclic prefix to obtain time-domain transmitted signals; removing the cyclic prefix at the receiving end; carrying out the fast Fourier transform on the signals with the cyclic prefix removed to obtain frequency-domain received signals; and carrying out the iterative detection decoding based on the multi-user combined frequency-domain balance on the frequency-domain received signals. The invention obtains the low signal envelope fluctuation performance under the condition of maintaining the frequency spectrum efficiency, and the transmission reliability is ensured in lower complexity by the iterative received signal processing method based on the multi-user combined frequency-domain balance.

An on frequency repeater for wireless networks with feedback oscillation detection is disclosed. The on frequency repeater includes an automatic gain control loop which samples amplified signal envelope. The automatic gain control loop is monitored and a characteristic saw tooth pattern in the gain control loop indicating feedback oscillation is detected. A nonlinear gain expander circuit may be periodically activated to allow feedback oscillation detection in repeater applications employing linearized amplifiers.

A system and a method for providing a secure wireless ad-hoc network in a wireless communication system having at least two transceivers coupled by a wireless transmission link are disclosed. The method includes receiving a data transmission at a first transceiver from a second transceiver, wherein the data transmission identifies a source of a signal in the data transmission and the signal is identified by a signal envelope; detecting a deep fade in the data transmission, wherein the first and second transceivers are configured to sample the source of the signal in the data transmission; determining whether the received signal exceeds a predetermined threshold for deep fades, wherein the predetermined threshold is preset by the first and second transceivers; generating a bit-string corresponding to each of the transceivers based on channel fading information relating to the wireless transmission link; and, using the bit-string, generating a key.

The invention concerns a module (402) for binary coding of a signal envelope, comprising a coding module (502) of a first variable length mode. According to the invention, the coding module of a first mode incorporates an envelope saturation detector and said coding module (402) also comprises a second coding module (503) of a second mode, arranged parallel to the coding module (502) of the first mode, and a mode selector (504) capable of maintaining one of the two coding modes, based on a code length criterion and on the result derived from the envelope saturation detector. The invention is applicable to coding by audiofrequency signal transform.

A transmitter comprises an amplifier operable for receiving an input signal and amplifying the input signal to produce an output signal. A power supply is coupled to the amplifier for supplying power to the amplifier, the power supply operable for tracking the input signal and varying the level of power supplied to the amplifier in response to variation of the input signal. A predistortion circuit is coupled to the power supply, the predistortion circuit operable for receiving the input signal and predistorting the input signal to the power supply for addressing input signal tracking capabilities of the power supply.