Method for generating waveforms of non-sinusoidal orthogonal bandpass signals in time domain

Abstract

The invention provides a method for generating waveforms in radio communication and in particular provides a method for generating waveforms of non-sinusoidal orthogonal bandpass signals in time domain. The method has the beneficial effects of simple hardware structure and low implementation cost. The method can generate the waveforms, with in-band energy concentration the same as that of the prolate spheroidal wave function (PSWF) of baseband, of the orthogonal bandpass signals in time domain in any frequency range, ensures the number of the orthogonal waveforms to double that of the original PSWF waveforms and can be used for improving the frequency band use ratios and the power use ratios of the radio communication systems. The generation method is characterized by determining the parameters according to the spectrum mapping relation and the sampling theorem, solving the numerical solution of PSWF of baseband by the numerical solution method, converting the signals to the analog signal waveforms through analog-to-digital conversion and low-pass filtering and carrying out time domain multiplication on the analog signal waveforms and the same frequency orthogonal sine / cosine functions with phase difference shown in the specification respectively, thereby obtaining the orthogonal waveforms.

Description

technical field The invention relates to a method for generating waveforms in radio communication, in particular to a method for generating non-sinusoidal time-domain quadrature band-pass signal waveforms. Background technique In radio communication systems, it is of great significance to design band-pass signal waveforms with time-domain orthogonality and high energy concentration. The time-domain orthogonal characteristic is beneficial to multi-channel modulation and demodulation, and improves the frequency band utilization rate, and the high energy concentration is beneficial to avoiding out-of-band interference and improving power utilization rate. The ellipsoidal wave function (prolate spheroidal wave functions, PSWF) has biorthogonality in the time domain, and has been proved to be the time-limited band-limited function with the highest energy concentration (see literature: D.Slepian and H.O.Pollak, Prolate spheroidal wave functions , Fourier analysis, and uncertainty...

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Problems solved by technology

However, this method also has shortcomings: due to the digital-to-analog conversion, the highest frequency and accuracy of the signal that can be generated are restricted and affected by the conversion rate and conversion accuracy of the D / A chip; The hardware index of the analog-to-analog conversion device, if it is to generate a high-frequency and high-precision ellipsoidal wave function signal, the requirements for the required digital-to-analog conversion device are very high, and the design of the subsequent band-pass analog filter is also more difficult , so the hardware cost of implementation is very high; adopting this method to generate a bandpass ellipsoidal wave function signal requires oversampling the signal, and storing all sampled values ​​in a cycle in a lookup table, in some cases (for example The ellipsoidal wave function signal to be generated is a high-frequency signal and a narrow-band signal), and the number of samples in one cycle of the signal will be very large, so the required storage space will also be large, especially when multiple signals need to be generated In this case, the requirements for storage hardware are increased, and the amount of data is too large, the amount of calculation required for digital signal processing of the signal is very large, and higher requirements are placed on the processing speed of the hardware

It can be seen that the above two methods have their own shortcomings and limitations when generating band-pass ellipsoidal wave function waveforms with time-domain orthogonality and high energy concentration.

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