摘要:
There is disclosed a method of controlling an input to an envelope modulated power supply of an envelope tracking amplification stage, comprising: generating an envelope signal representing the envelope of a signal to be amplified; applying a shaping function to the envelope signal to generate a shaped envelope signal, including: clipping the shaped envelope signal at high input envelope values; and providing the shaped envelope signal as an input signal to the envelope modulated power supply.
摘要:
When, in conventional sound systems, signals of sounds collected by a microphone are amplified and the amplified signals are applied to an ear by an earphone and a headphone, too loud sounds and environmental noises are unpleasant, and the intelligibility of words are poor. Hence, such problems are to be addressed. In addition, downsizing and performance improvement for sound apparatuses are to be accomplished. A signal having undergone an amplitude limitation with reference to an output potential of a high cut filter 17 which is an output by a low cut filter 12 in a high frequency band and inverted by an inverter 14 is added with, by an adder 15, an output signal from the high cut filter 17, and an addition signal is output.
摘要:
A method for operating a user equipment (UE) employing a CDMA technique, the method comprising: means for combining a plurality of spread spectrum data signals, wherein the output of the combining is a combined signal having a fluctuating power level corresponding to the data signals; means for modulating the combined signal to produce an RF signal for transmission; means for measuring an average power of the output of the combining means for a selected time period; means for adaptively limiting an output of the combined means to a calculated level based at least in part on the measured average power; and means for transmitting the RF signal.
摘要:
A peak limiter for use in a system for amplifying a multi-carrier signal receives a baseband signal of each carrier of the multi-carrier signal. The multi-carrier signal is computationally estimated to have carriers combined in an RF band, and obtains power information of the multi-carrier signal to limit an amplitude of the baseband signal based on the power information of the estimated multi-carrier signal to thereby provide peak-limited baseband signals. Thus, the distortion generated by performing the unnecessary peak limitation can be effectively prevented to thereby improve the reliability of the entire system.
摘要:
The invention reduces transient peaks in signals transmitted in CDMA communication systems. A plurality of spread spectrum data signals are combined into a combined signal having fluctuating power level corresponding to the combination of the data signals. The combined signal is modulated to produce an RF signal for transmission. The average power of the combined signal is measured over a selected time period. The combined signal power level is adaptively limited to a calculated power level based at least in part on the measured power.
摘要:
An apparatus, such as a coherent optical receiver, includes a transimpedance amplifier (TIA) with differential outputs, and a multi-tanh type current limiter (300) connected across the differential outputs of the transimpedance amplifier. The multi-tanh type current limiter includes two tanh-type current limiters (330) shifted in voltage and connected to subtract an output current thereof from an output current of the TIA.
摘要:
The application relates to a compressor circuit for a listening device, the compressor circuit comprising a pair of input terminals and a pair of output terminals, the compressor circuit being adapted for receiving an electric input signal representing an audio signal with an input voltage swing V ipp at the input terminals and for providing a possibly compressed version of the input signal as an output signal with an output voltage swing V opp at the output terminals. The application further relates to a listening device and to the use of the compressor circuit. The object of the present application is to provide a compressor circuit with a proper functioning also at relatively low input levels. The problem is solved in that an AC to DC voltage converter for generating a DC-control voltage based on the electric input signal or an AC signal derived therefrom, and a voltage controlled resistance for providing an output voltage swing Vopp controlled by the DC-control voltage, wherein the compressor circuit is energized by the electric input signal. An advantage thereof is that a compressor circuit facilitating a flexible adjustment of the maximum output level is provided. The invention may e.g. be used in portable and non-powered listening devices, e.g. headsets or active ear protection devices.
摘要:
A nonlinear compensating circuit, a base-station apparatus and a transmission power clipping method for executing a clipping operation beneficial against nonlinear characteristics of a high output amplifier at the transmitting end even in the case of multicarrier amplification. A plurality of power converting circuits calculate power values of respective input signals. An adder adds up the calculated power values to obtain a synthetic power value P. A divider divides a predetermined threshold value T by the synthetic power value P. When the divided value T/P is equal to or more than 1, a determining circuit outputs a clip control signal for turning off the clipping operation to a plurality of clipping circuits. On the other hand, when the divided value T/P is less than 1, the determining circuit outputs a clip control signal for turning on the clipping operation, which includes a square root of the divided value T/P obtained by the divider, (T/P) 1/2 , to the clipping circuits.