Question
A customer would like to confirm the Downconverter Modes 3 and 4 specified in
Table 18 of the AD6655 datasheet.
For mode 3 for example (NCO and half-band filter) one can:
Write 0x24 to Register 0x100 and
write 0x03 to register 0x103 (not sure if the high or low pass fiter is
selected here).
For mode 4 (NCO, half-band filter and FIR filter) one can:
Write 0x24 to Register 0x100
write 0x03 to register 0x103
write 0x09 to register 0x102 (FIR filter with a gain of 1)
Is this true to say?
Answer
For Mode 3:
Register 0x103 should be a 0x01 for low pass mode (typically used) or 0x03 for
high pass mode
Also for Complex Output mode register 0x102 should be written with 0x0E to
disable the fs/8 output mix, enable complex output mode, FIR gain of 1
For Mode 4:
Register 0x103 should be a 0x01 for low pass mode (typically used) or 0x03 for
high pass mode
Also for Complex Output mode register 0x102 should be written with 0x0F to
disable the fs/8 output mix, enable complex output mode, FIR gain of 1 and
enable the FIR filter