KR950030555A - Digital Modulation Method and Apparatus - Google Patents

Abstract

In the digital modulation method and apparatus according to the present invention, when a digital signal is transmitted by a linear modulation method using an amplifier having a nonlinear characteristic, an NRZ data string consisting of a plurality of input bits is received, and a point in a corresponding signal space is received. Depending on the amplification degree of the amplifier used, transform the spatial coordinates as previously stored in the standard spatial coordinates, modulate the signal on the carrier, and then amplify and transmit the signal to improve the bandwidth characteristics and error probability performance of the linear modulation signal. It can be improved.

Description

Digital Modulation Method and Apparatus

Since this is an open matter, no full text was included.

FIG. 1 is a block diagram showing a conventional digital modulator, and an example of using an adaptive linear distortion device to compensate for the effects of nonlinearity of an amplifier. FIG. 2 is a block diagram showing a digital modulator according to the present invention.

Claims (5)

A correction step of modifying an amplitude of the digital data bit string by the correction amount by inputting the digital data bit string; A modulation process of performing digital linear modulation on a signal output from the correction process with a predetermined carrier signal; An amplifying step of amplifying the signal output in the modulation process with as much power as required for transmission; A power calculation process of detecting an output signal of the amplification process and calculating and outputting an average power of a current output; And predicting the non-linearity degree in the amplification process according to the output control signal by inputting the signal output from the power calculation process, the digital data bit string, and a predetermined output control signal. And a correction amount generating process of adaptively determining the non-linear degree according to electric power and generating a correction amount for compensating the non-linear degree. A spatial degree converting unit configured to output a digital signal corrected by converting an amplitude of the digital data bit string by the correction amount as a digital data bit string as an input; A modulator for outputting an analog modulated signal by performing digital linear modulation on a signal output from the spatial degree converter by a predetermined carrier signal; An amplification degree controlled by an external output control signal, the amplifying unit amplifying the signal output from the modulating unit as much power as required for transmission; A power calculator which detects an output signal of the amplifier and calculates and outputs an average power of a current output; And predicting the nonlinearity of the amplifier according to the output control signal by inputting the signal output from the power calculator, the digital data bit string, and the output control signal, and according to the power of the signal currently output from the amplifier. And a correction amount generator for adaptively determining the non-linearity of the amplification unit and supplying a correction amount for compensating the non-linearity to the spatiality converter. 3. The spatial degree changing unit receives an NRZ data string consisting of a plurality of input bits and converts the data into one point in a corresponding signal space, and stores the space in advance in standard spatial coordinates according to the amplification degree of the amplifier used. Digital modulator, characterized in that for transforming the coordinates. The digital modulator of claim 2, wherein the amplification unit has a nonlinear characteristic with respect to amplitude and phase. The digital modulation apparatus as claimed in claim 2, wherein the correction amount generating unit outputs a degree of deformation of the spatial coordinate point represented by the digital data bit string as a correction amount. ※ Note: The disclosure is based on the initial application.