Need Help with FIR II TDM.

Hi,

Sorry for the delay. Sorry if there is any confusion with my previous explanation. I am not referring to 2 channels but just trying to explain using serialization of two streams into one. Let me try to explain in a different way using the following example:

Assuming the input sample rate = 50MSPS. By default the required clock rate = 50MHz. However, in order to reduce the number of multipliers used, we use TDM = 2 as example to halve the multipliers. With TDM = 2, the required clock rate to the FIR IP is doubled = 100MHz.

This reduces the number of multipliers by 2x but increases logic utilization to implement the Serializer and Deserializer. At the top level, the operation of the serializer and deserializer are transparent to the user. What user need to do, is to supply 2x clock rate than the sample rate or the frequency and sample rate that you configure in IP.

Back to your configuration case, you have input sample rate = 15MSPS and clock rate = 60MHz. In other words, you are configuring the IP to implement TDM = 4. The number of multipliers utilized should reduced by 4x. During your test, you should supply input with sample rate of 15MSPS but not the 7.5MSPS because the IP is expecting 15MSPS. With 15MSPS, you would get 15MSPS at output as well. If you would like to supply 7.5MSPS, you should configure the same in the IP configuration.

Please let me know if there is any concern. Thank you.