USRP RX Decimation Rate


#1

Hi All,

I’m a new USRP user. Kindly, I will be very appreciated if someone
could
tell me what is the decimation range of the USRP RX path? I’m really
confused. Is it linear range from [1,2,3,4,…] ?or it is power of 2
[2,4,8,16,…]?

Thank you in advance.

Firas

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#2

On 4/21/07, Eng. Firas removed_email_address@domain.invalid wrote:

Hi All,

I’m a new USRP user. Kindly, I will be very appreciated if someone could
tell me what is the decimation range of the USRP RX path? I’m really
confused. Is it linear range from [1,2,3,4,…] ?or it is power of 2
[2,4,8,16,…]?

It’s linear and within 4 to 128 inclusive, according to
cic_dec_shifter.v located here:

http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/cic_dec_shifter.v

Brian


#3

Brian P. wrote:

It’s linear and within 4 to 128 inclusive, according to
cic_dec_shifter.v located here:

http://gnuradio.org/trac/browser/gnuradio/trunk/usrp/fpga/sdr_lib/cic_dec_shifter.v

The CIC decimator does 4 through 128, but this is followed by a halfband
decimator which multiplies this by a factor of 2. Thus, it only does
multiples of 2. 4, 6, 8, 10, 12, 14, 16, 18. 20, etc. Up to 256
total.

Matt


#4

On 4/22/07, Eng. Firas removed_email_address@domain.invalid wrote:

Thank you Brian, Matt.

If the CIC starts linearly from 4 to 128, and followed by decimate by 2 Half
Band Filter (HBF) Then [CIC+HBF] should give us the following range
[8,10,12,14,…,256], and not the range [2,4,6,8,…,256] , is
this correct ?

Correct.

Firas

Brian


#5

Eng. Firas wrote:

Firas

Thank you Brian, Matt.

If the CIC starts linearly from 4 to 128, and followed by decimate by 2
Half
Band Filter (HBF) Then [CIC+HBF] should give us the following range
[8,10,12,14,…,256], and not the range [2,4,6,8,…,256] ,
is
this correct ?

Firas

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http://www.nabble.com/USRP-RX-Decimation-Rate-tf3622054.html#a10123915
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