Pulse-frequency modulation

About: Pulse-frequency modulation is a research topic. Over the lifetime, 4151 publications have been published within this topic receiving 53039 citations. The topic is also known as: PFM.

Method for correcting distortion of modulation wave and transmitter

Abstract: PURPOSE: To correct the distortion of a modulation wave. CONSTITUTION: A signal processing section 3 applies digital signal processing to transmission information to provide the output of two couples of base band signals, a quadrature modulation section 7 converts a carrier into two signals with a prescribed phase difference and they are respectively multiplied with a couple of the above base band signals and the products are added and a modulation wave is outputted. In this case, a branching section 4 provided between the quadrature modulation section 7 and an output section 5 provides properly a modulation wave outputted from the quadrature modulation section 7 to the output section 5 and a detection section 6. Then the detection section 6 detects the modulation wave to provide the output of an envelope signal being a signal of the envelope of the modulation wave and a control section 32 provides the output of a distortion correction signal to a signal processing section 3 so as to minimize the amplitude fluctuation of the envelope signal thereby correcting distortion of the modulation wave.

Device for the transmission of rectangular synchronous information pulses

Abstract: A system for the transmission of rectangular synchronous information pulses from an information source to an information consumer within a prescribed frequency band in which the information pulse is in coincidence with different pulses from a series equidistant clock pulse generator, in which system use is made of a switching modulated device for the direct modulation of rectangular information pulses on to a rectangular carrier oscillator. A band-pass filter and a correction circuit follow the switching modulation device for the suppression of unwanted modulation products generated in the switching modulation device.

Pll modulation circuit, radio transmission device, and radio communication device

Abstract: Provided are a PLL modulation circuit, a radio transmission device, and a radio communication device capable of maintaining a modulation accuracy for modulation of a wide band. The PLL modulation circuit (100) includes: a PLL unit (110), first modulation signal input means for inputting a first modulation signal to a divider (112) or a phase comparator (113) of the PLL unit (110); second modulation signal input means for DA converting the digital modulation signal in a DA converter (116) to generate an analog second modulation signal and inputting it to a voltage control oscillator (111) of the PLL unit (110); a second divider for dividing the output signal of the voltage control oscillator (111); and control means for generating a center frequency control signal, a gain control signal, and a second division ration control signal according to the channel selection signal and the control voltage inputted to the voltage control oscillator (111) and supplying them to the divider (112), the DA converter (116), and the second divider (114), respectively.

Resonator optical gyroscope having input beam modulation optimized for high sensitivity and low bias

Abstract: Systems and methods for optimizing input beam modulation for high gyro sensitivity and low bias errors. The present invention is a resonator optical gyroscope having an optimized phase-modulation amplitude (frequency) for a selected modulation frequency (amplitude) that maximizes the gyro signal-to-noise (S/N) sensitivity. For selected values of the phase modulation amplitude, the polarization cross-coupling induced intensity modulation can be nulled. By setting the phase modulation amplitudes substantially close to these nulling points (e.g. M= 3.832 or 7.016 radians, which causes the first order Bessel function to be zero J 1(M) = 0) and then optimizing the modulation frequency, the intensity modulation induced bias is reduced to zero and gyro S/N sensitivity is maximized.