ZHCSNC3B February 2021 – October 2022 ADC3561 , ADC3562 , ADC3563
PRODUCTION DATA
The ADC356x includes an optional on-chip digital down conversion (DDC) decimation filter that can be enabled via SPI register settings. It supports complex decimation by 2, 4, 8, 16 and 32 using a digital mixer and a 32-bit numerically controlled oscillator (NCO) as shown in Figure 8-21. Furthermore it supports a mode with real decimation where the complex mixer is bypassed (NCO should be set to 0 for lowest power consumption) and the digital filter acts as a low pass filter.
Internally the decimation filter calculations are performed with a 20-bit resolution in order to avoid any SNR degradation due to quantization noise. The Output Formatter truncates to the selected resolution prior to outputting the data on the digital interface.