Improving the frequency resolution of digitally synthesized periodic signals by a sequential addressing scheme

Abstract

In the digital synthesis of wideband periodic signals using an Arbitrary Waveform Generator (AWG), the frequency resolution and spectral complexity of the synthesized signals are commonly limited by the memory capacity and clock frequency of the AWG. This paper proposes a novel sequential addressing scheme and then presents several sequences to improve the frequency resolution of the synthesized periodic signals without changing their spectral envelopes and basic time-domain characteristics under the condition of a fixed memory capacity and a fixed clock frequency. The main idea of the scheme is using the address generator in an AWG to program and produce addresses to read fixed waveform data in variable order, and thus to generate waveforms of various periods and profiles. The scheme is applied in simulating signal scenarios for military communication countermeasure experiments, and achieves high performance.

Exact analysis of spurious signals in Direct Digital Frequency Synthesizers due to amplitude quantization

“…in the case of truncation quantization, with the relative amplitude of the second strongest frequency component is equal to 2 10 lg(4 | (3 mod ) | ). E X U U According to Tab.2, The relative amplitude of the second strongest frequency component of ( ) e n is mainly subject to .…”

“…In addition to the above requirements, hardware designers are targeting more and more cost-saving and power-saving solutions [1,2] . But the most important specification of frequency synthesis is spectral purity [3] .…”

An iterative algorithm for optimal design of non-frequency-selective FIR digital filters

“…In this section, the optimization effect of the proposed algorithm is examined by the design of an inverse-sinc compensation filter which is used to compensate the droop of the sinc envelope caused by a digital to analog converter in a telecommunication system [14] . The filter has a linear phase response, and the desired frequency response is…”