10 results about "Automatic frequency control" patented technology

The utility model provides a phase-locked loop circuit and an image sensor, and the phase-locked loop circuit comprises a phase frequency detector, a charge pump circuit, a switching circuit, an inductance capacitance voltage-controlled oscillator, an automatic frequency control circuit, and a detection control circuit. The automatic frequency control circuit controls the switching circuit to output a voltage reference signal and output a digital code signal, so that the capacitance in the inductance-capacitance voltage-controlled oscillator is changed, the frequency of an output signal of the phase-locked loop circuit is further changed, after calibration is finished, the phase frequency detector and the charge pump circuit output a changed first voltage signal, and the charge pump circuit outputs a second voltage signal. The capacitance of the inductance capacitance voltage-controlled oscillator and the frequency of an output signal of the phase-locked loop circuit are changed, and the detection control circuit outputs a closing signal to close the automatic frequency control circuit, so that additional circuit power consumption is reduced; digital code signals input by the inductance-capacitance voltage-controlled oscillator are not changed, and disturbance influence is eliminated.

The invention provides an adaptive control method and system for an accelerator klystron, and electronic equipment, and the method comprises the steps: collecting a reverse wave signal in a microwave signal which is generated by an excitation source, is amplified by the klystron, and is inputted to an accelerating tube, and obtaining the current output frequency of the excitation source; performing I / Q orthogonal demodulation on the reverse wave signal to obtain an I / Q signal, and calculating the frequency deviation between the current resonant frequency of the accelerating tube and the current output frequency of the excitation source; and according to the frequency deviation, outputting a frequency control instruction to the excitation source so as to adjust the output frequency of the excitation source, and enabling the current output frequency of the excitation source to track the current resonant frequency of the accelerating tube. By calculating the frequency deviation and directly outputting the control instruction to adjust the output frequency of the excitation source, the technical problems of control object dislocation and response lag existing in a traditional automatic frequency control system are solved.

The utility model proposes a phase-locked loop circuit and an image sensor, the phase-locked loop circuit comprises a phase frequency detector, a charge pump circuit, a switching circuit, an inductance capacitance voltage-controlled oscillator and an automatic frequency control circuit, in a calibration mode, the automatic frequency control circuit controls the switching circuit to output a voltage reference signal, and the inductance capacitance voltage-controlled oscillator outputs the voltage reference signal. The phase-locked loop circuit changes the frequency of an output signal of the phase-locked loop circuit, compares the frequency of the output signal with a clock reference signal, outputs a correspondingly changed digital code value according to a comparison result, and the digital code value changes according to a dichotomy rule, so that the capacitance and frequency of the inductance-capacitance voltage-controlled oscillator are rapidly changed, and the calibration efficiency is improved. After calibration is finished, the phase frequency detector and the charge pump circuit output a variable first voltage signal, and the capacitance of the inductance capacitance voltage-controlled oscillator and the frequency of an output signal of the phase-locked loop circuit are changed.

Systems and methods for performing automatic frequency control are provided. Instead of relying on individual frequency tuners for each channel of a multi-channel receiver system, the present subject matter uses a single frequency tuner for receiving each channel of the multi-channel receiver system. A locked demodulator may be designated as a reference demodulator and frequency offset values associated with the reference demodulator may be applied to other demodulators of the multi-channel receiver. These frequency offset values may be used by individual demodulators of each channel for correcting corresponding frequency offsets.

In one embodiment, a device determines a physical location of a mobile client of wireless network. The device performs a frequency lookup for the mobile client from an AFC service using the physical location of the mobile client. The device selects a frequency to be used by the mobile client based on the frequency lookup. The device causes the mobile client to use the frequency to communicate with the wireless network.

The invention relates to the technical field of radio frequency communication, and provides a carrier frequency offset compensation method and device, equipment, a medium and a program product, and the method comprises the steps: carrying out the frequency offset compensation of a first subframe of a radio frequency operation according to a normalized frequency offset in a preset duration after a radio frequency module is started if the radio frequency operation is carried out; wherein the normalized frequency offset is obtained by dividing a historical carrier frequency by a historical carrier frequency offset value, the historical carrier frequency offset value is a carrier frequency offset value obtained by carrying out carrier frequency offset measurement on a first subframe within a preset duration after the historical radio frequency module is started, and the historical carrier frequency is the carrier frequency of the historical radio frequency module; the radio frequency parameter of the historical radio frequency module is the same as the radio frequency parameter of the radio frequency module; and performing frequency offset compensation on subframes except the first subframe in the radio frequency operation according to a preset automatic frequency control method. In this way, the first subframe of the radio frequency operation can be effectively compensated, so that the residual carrier frequency offset of the first subframe is significantly reduced.

The invention provides an adaptive control method and system for a klystron of a medical accelerator, the medical accelerator comprises an excitation source used for generating microwave pulses and an accelerating tube used for accelerating injected electronic pulses, and the method comprises the following steps: acquiring a reflected wave signal at the input end of the accelerating tube; calculating the current resonant frequency of the accelerating tube according to the reflected wave signal; and calculating the frequency deviation between the current output frequency of the excitation source and the current resonant frequency of the accelerating tube, and outputting a frequency tuning instruction to the excitation source based on the frequency deviation so as to adjust the output frequency of the excitation source and enable the output frequency of the excitation source to track the resonant frequency of the accelerating tube. The technical problem of logic failure caused by dislocation of a control object in a traditional automatic frequency control scheme is solved, the output frequency of the excitation source is dynamically adjusted through closed-loop control, efficient injection of microwave energy is ensured, and the system stability and clinical reliability of the system are improved to a great extent.

A communication system embeds a trust message into an outbound control channel signal derived from a GPS reference signal associated with trunked communications. The trust message is used as a basis for incrementally expanding the subscriber's automatic frequency control (AFC) range beyond its pre-stored default limits to enable re-tuning a temperature compensated crystal oscillator (TCXO) that has drifted off frequency. Coarse-tuning of the subscriber TCXO is based on a measured frequency error of a control channel outbound transmission determined to fall within the expanded AFC range of the subscriber. Additionally, an inbound signal frequency error may be measured by the base station, and reported to the subscriber to use for fine-tuning the TCXO.

The application discloses a communication signal processing method and device, electronic equipment and storage medium, wherein the communication signal processing method comprises the following steps: in the case that a first frequency offset value of a first communication signal is determined to obtain a first frequency offset value, if an automatic frequency control module does not act on the first communication signal, a first frequency point position is obtained by summing the first frequency offset value and a preset frequency point position, and single tone interference in the first communication signal is eliminated according to the first frequency point position; if the automatic frequency control module acts on the first communication signal, a second frequency offset value of a second communication signal is determined to obtain a second frequency offset value, a second frequency point position is obtained by summing the second frequency offset value and the preset frequency point position, and single tone interference in the second communication signal is eliminated according to the second frequency point position. The application solves the technical problem that the automatic control module will affect the position of the single tone interference which has been determined, cause the position of the single tone interference to be inaccurate, affect the effect of single tone interference elimination, and further affect the performance of the communication signal.