Dither Technology In The Applications Of Adc And The Realization Of Validation

ADC (analog-to-digital Converter) converts the analog signal into digital signal,which can be processed by DSP (digital signal processor). With the rapid developmentof chip manufacturing technology, DSP technology is booming, and it processes moreand more quickly, which requires the ADC provide higher speed. In the application ofhigh speed ADC, especially for communication field, high dynamic performance ofADC is required to reduce the adjacent signal interference. This research is using dithertechnology to reduce harmonic components in the frequency spectrum of the signal afteranalog-to-digital conversion, which effectively improves the SFDR (spurious freedynamic range) of high-speed ADC.Firstly, this article introduces the principle of ADC, and makes a brief classificationand overview of types of ADCs. Then it introduces the main ADC static and dynamicperformance parameters, especially focuses on SFDR.Secondly, the principle of Dither technology is discussed, including several dithersignal generating methods and types of dither signals. Subsequently it analyses thepositive effect on ADC performance of small amplitude dither and large amplitudedither. Then the way of adding dither signal to the input signal is proposed.Subsequently two kinds of typical dither signal generating circuit based on abovediscussion are designed, which contains broadband dither and narrowband dithergenerating circuit.Finally, in Chapter Four, the signal integrity is introduced, main factors affectingthe signal integrity of high-speed PCB is discussed. According to several types of ditherstructures, a system was designed to verify the capability of dither technology in theactual verification board system.Then each module of the test board is introduced indetail. After the debugging work was finished, both the broadband dither andnarrowband dither were validated.