Thank you for your response!
We need to use the sampling rate of 4 MHz. How can I deal with this problem?
Actually we have been running the same application on several USRPs (N200 and N210), and there was no such warning.
From: Marcus D. Leech [mailto:address@hidden
Sent: Monday, November 12, 2012 11:29 AM
To: Ting Wu
Subject: Re: [Discuss-gnuradio] Requested decimation is odd
I am using USRP N200 with LFRX daughter board. The newest version of images has been loaded.
The sampling rate is set as 4 MHz. There is constantly a UHD warning:
The requested decimation is odd; the user should expect CIC rolloff.
Select an even decimation to ensure that a halfband filter is enabled.
How do I change the decimation value?
And what value should I set it?
100e6 / 4e6 = 25
Which is odd value which changes the "line up" of filtering in the FPGA.
Select a sample rate that results in an even decimation value, unless you can live with the edge roll-off for an odd value.
Shirleys Bay Radio Astronomy Consortium