46results about How to "Implement Automatic Gain Control" patented technology

The invention discloses a method and circuit for avoiding the overshoot of a power amplifier. The method comprises the steps of: adding an initial attenuation voltage to an electrically controlled attenuator when the power amplifier is powered up, and setting a relatively large attenuation value; keeping the magnitude of the attenuation voltage unchanged when a demodulation level output by a directional coupler changed between zero and a first reference level; controlling the attenuation voltage to increase with the increase of the demodulation level when the demodulation level changes between the first reference level and a second reference level; controlling the attenuation voltage to decrease with the increase of the demodulation level when the demodulation level changes between the second reference level and a third reference level; and keeping the magnitude of the attenuation voltage to be identical with the initial attenuation voltage when the demodulation level is larger than the third reference level. According to the invention, when the power amplifier is powered up, the relatively large attenuation value is set to the electrically controlled attenuator to enable signal attenuation to reach a suitable level, so that the overshoot of the output power is avoided.

The present invention discloses a gain control device based on dual-threshold receiver and a control method thereof, which relates to the technical field of communication. The device comprises: a network module circuit, an variable amplitude local oscillator output circuit, an analog-digital conversion AD circuit, a digital-analog conversion DA circuit, a control circuit and a receiver analog part circuit; the control method comprises: opening the AGC function, the upper computer setting average voltage scope of the receiver, average voltage value of the AD acquisition receiver by network control; the CPU comparing the voltage value acquired with the set voltage value, adjusting the step value according to the deviation to the threshold; the CPU based on the step value controlling the DA circuit to output a voltage to control the amplitude of local oscillator output, making the audio output average voltage of the receiver to be constant in the target scope through multiple adjustments. The control device and the method based on dual-threshold receiver of the present invention can make the audio output average value of receiver to be constant in target scope rapidly.

The invention relates to a linear dynamic calibration source system, in particular to a high-accuracy high-linearity high-temperature-stability dynamic calibration source system. According to the high-accuracy high-linearity high-temperature-stability dynamic calibration source system, automatic gain control of a power level is achieved by using of a negative feedback loop. Power output in a large dynamic range is achieved by using of an electronic stored program control attenuator. In an automatic gain control loop circuit, high accuracy degree of power is achieved by using of a synchronous real-time compensating radio frequency detector, linear compensation and temperature compensation. High-linearity output of the power is achieved in the whole dynamic range, and consistency of the power output in the whole working temperature range is ensured.

The invention discloses a multi-path data acquiring system based on FPGA, which mainly solves the problems of small signal acquiring range and poor acquiring precision of the prior multi-path acquiring system. The multi-path data acquiring system comprises a multi-path selector, a programmable-gain amplifier, an AD converter and an FPGA data processing module, wherein the FPGA data processing module sends an address signal to the multi-path selector and also sends a magnification signal to the programmable-gain amplifier; the multi-path selector selects an external analog signal according to the address signal to enter the programmable-gain amplifier; after amplifying the input analog signal, the programmable-gain amplifier outputs the analog signal to the AD converter; the AD converter samples the input analog signal, quantifies the analog signal to form a digital signal and transmits the digital signal to the FPGA data processing module; and the FPGA data processing module transmitsthe input data to a host computer after sequencing, wave filtering and table searching. The invention has the advantages of wide signal acquisition range, high precision can convenient acquisition path expansion, thereby being suitable for the signal acquisition of an industrial monitoring and sensing network.