A method & error analysis of phase difference measurement based on digital quadrature transformation;

Structures similar to analog receiver are often applied in the design of direct IF sampling,however,the digital quadrature transformation based on polyphase structure does not need quadrature LO,therefore,it’s more suitable for real-time processing system in terms of structure.

In order to implement processing functions of receiver in communication and radar systems by software as far as possible, it is necessary to use the direct IF sampling and digital quadrature transformation to obtain baseband inphase and quadrature components.

The application of IP core-based FIR filter to digital orthogonal transformation;

This paper investigates the principle of the digital orthogonal transformation based on multiphase filtering,and proved that the interpolation delay filters could be replaced with branch filters from a multiphase filter according to the theory of multi-sampling rate signal processing.

The design of the high speed digital orthogonal transformer which architecture based on the digital channelization in frequency domain is introduced in this paper.

An approach for designing digital-intermediate frequency(IF) receiver is introduced,the principle analysis and deduction of all parts of the receiver are performed including design of available-band filter,Analog-to-Digital Converter(ADC),digital orthogonal transforms based on digital polyphase filter,decimation filter,baseband signal processing unit.

Then,according to the signal property,the signal generation technique based on AD9857 quadrature digital upconverter is introduced.

The hardware circuit of radar echo simulator is designed, including FPGA and DSP circuit, digital quadrature upconverter circuit, baseband data access circuit.