TV_RX anti-aliasing filter

Hello everyone,

I am a new user and recently set up the USRP and TV_RX boards to receive
FM radio and now trying to take the dive into capturing HDTV. I had a
basic, maybe dumb question on the presence of a low pass filter before
the A/D converter. Does anyone know if the TV_RX board has an
anti-aliasing low pass filter on it? Or within the Microtune 4937 tuner
module? I looked at the schematic for the daughter board and the data
sheet for 4937 but I am not sure if there is one. The TV_RX I got has an
IF frequency of 44MHz and I understand that undersampling it at 64 Msps
with the A/D converter causes it to fold to 20 MHz. I wanted to know
whether there is or there needs to be a low pass filter before the A/D
converter to suppress any energy in the lower frequencies before
sampling.

Thanks,
Nirali P.
DSP Application Engineer
Coherent Logix, Inc

Nirali P. wrote:

Hello everyone,

I am a new user and recently set up the USRP and TV_RX boards to receive FM radio and now trying to take the dive into capturing HDTV. I had a basic, maybe dumb question on the presence of a low pass filter before the A/D converter. Does anyone know if the TV_RX board has an anti-aliasing low pass filter on it? Or within the Microtune 4937 tuner module? I looked at the schematic for the daughter board and the data sheet for 4937 but I am not sure if there is one. The TV_RX I got has an IF frequency of 44MHz and I understand that undersampling it at 64 Msps with the A/D converter causes it to fold to 20 MHz. I wanted to know whether there is or there needs to be a low pass filter before the A/D converter to suppress any energy in the lower frequencies before sampling.

The output from the tuner module has already been filtered by a SAW
filter, so there is no need for any further filtering. There is only
significant energy in the desired band.

Matt

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