SBASA91 December 2020 TLV320ADC3120
For applications that require an even higher SNR than that supported for each channel, the device digital summing mode can be used. In this mode, the digital record data are summed up across the channel with an equal weightage factor, which helps in reducing the effective record noise. Table 8-20 lists the configuration settings available for channel summing mode.
|P0_R107_D[3:2] : CH_SUM[1:0]||CHANNEL SUMMING MODE FOR INPUT CHANNELS||SNR AND DYNAMIC RANGE BOOST|
|00 (default)||Channel summing mode is disabled||Not applicable|
|01||Output channel 1 = (input channel 1 + input channel 2) / 2||Around 3-dB boost in SNR and dynamic range|
|Output channel 2 = (input channel 1 + input channel 2) / 2|
|10||Reserved (do not use this setting)||Not applicable|
|11||Reserved (do not use this setting)||Not applicable|
The device additionally supports a fully programmable mixer feature that can mix the various input channels with their custom programmable scale factor to generate the final output channels. The programmable mixer feature is available only if CH_SUM[1:0] is set to 2'b00. The mixer function is supported for all input channels. Figure 8-18 shows a block diagram that describes the mixer 1 operation to generate output channel 1. The programmable coefficients for the mixer operation are located in the Section 188.8.131.52 section.
A similar mixer operation is performed by mixer 2 to generate output channel 2.