ADA2200 Program filter setting and Output waveform calculation

Hi,

There are two questions about use ADA2200.

1. Regarding to the ADA2200 Program filter function, Could you please help to provide some reference data for the Program filter setting. The datasheet doesn't tell too much about it.

2. Regarding to the output waveform, the datasheet says -

In the default configuration, there are eight output sample periods during each RCLK cycle. There are four updated output samples while the RCLK signal is high. While RCLK is low, the fourth updated sample is held constant for four additional output sample periods.  (Page 13, Mixer section)

Does it means only half cycle waveform will be present (As below figure) ??  How to calculate the input waveform value?

Hear from you soon and thanks!

  • Hi

    A question about values:

    Calculate the cycle mean. This is done by sampling 8 consecutive output values (5 unique values+3 hold values) and taking the average value.

    The ADA2200 only give out 4 unique values+4 hold values ( value of the 4th unique value), as I can see in the datasheet page 6 (sample 0, 1, 2 and 3+4 hold samples)

     

    So where does the 5 unique values+3 hold values come from ?

     

    /Steffen

  • Hi Steffen,  

    You are correct.  The cycle mean is the average of 8 samples. 4 of which are unique, and 4 of which are hold values.

    Brian

  • Hi Brian

    I have an other question:

    In the MT-324 the BP1 and BP2 filter that I tried to use, but they has Corner/center frequency at Fsi/32 (Hz/Nyquist = 0.5) and I need to use them with Fsi/64 (Hz/Nyquist = 0.25), so that they have corner at my RLCK frequency as the default filter (this filter has a wide filter responce, wish does not filter noise very well, out of the signal.

    I have tried to change the 0x0024 for 4F to E0 , but this does not work, something else goes wrong - so is it possibly to get BP1 and/or BP2 with Fsi/64 and not Fsi/32 ?

    With mixer on.

    /Steffen

  • Unfortunately we do not have any bandpass filters with a center frequency of Fsi/64.

  • Is it possibly to get one ?, since the filter in MT-324 have different Corner frequency, so they are diffucult to use in a application.