TVRX Kit - A Few Queries

GNU Radio
1

I ordered Tvrx module and expect it to arrive at my place soon. Hope it
will
have a manual or imp guidelines on usage. Anyhow, I have a few basic
questions :

  1. What is range of the IF I can set its output to?

  2. Can I use it for HDTV reception?

  3. What is the max voltage swing in the output? Is there a DC offset in
    it?

Waiting for a reply.

Cheers!

2

I ordered Tvrx module and expect it to arrive at my place soon. Hope it
will have a manual or imp guidelines on usage.

The TVRX will not come with a manual or guidelines on usage. You can
find
the schematics at http://gnuradio.org/trac/browser/usrp-hw/trunk/tvrx
The TVRX module has a Microtune 4937 Tuner Module and here is a link to
the
datasheet for that
http://www.comsec.com/usrp/microtune/4937-DI5-3x8899-2.pdf

  1. What is range of the IF I can set its output to?
    It has a fixed IF at 44Mhz I believe. A different version of the same
    tuner
    module comes with 5.75Mhz IF. Matt, please correct me if I am wrong.
  1. Can I use it for HDTV reception?
    Yes you can use it for HDTV reception. I am trying to do the same thing
    and
    am halfway there. I suggest you start with FM reception or something
    pretty
    basic using examples in gnuradio-examples directory.
  1. What is the max voltage swing in the output? Is there a DC offset in
    it?
    Ref datasheet mentioned above.

Nirali P.

3

Matt E. wrote:

Yes, the shippingones have an IF of 44 MHz. The older ones were 5.75
MHz, but from the user’s point of view, it doesn’t matter. You don’t
need to know the IF.

Matt

Actually that’s something I was curious about as well. I’ll likely be
picking up a TV_RX for this project here:

http://tech.groups.yahoo.com/group/sbrac-astronomy/

In the next few months. The dish surface is good to about 1.5Ghz, but
was originally designed for
ballpark 400Mhz. I’m trying to get a multi-faceted radio astronomy
and SETI program going on this
thing, and Pulsars are stronger down around 400Mhz than at 1420Mhz.
The dish is 18M or so
in diameter.

So, anything that works with the DBS_RX works also with the TV_RX? Is
the tuner real-mode only,
and do you synthesize I and Q in the FPGA?

4

If IF is at 44MHz, is it further downconverted(to around 5-15MHz) before
being fed to the ADC? I just want to know this out of curiosity. Pls let
me
know.

Cheers!
Prasanna

5

So, anything that works with the DBS_RX works also with the TV_RX?

yes

Is
the tuner real-mode only,

It doesn’t matter. But yes, the analog signal is real

and do you synthesize I and Q in the FPGA

yes, but again, it doesn’t matter.

All that matters is that you get a 6 MHz wide signal at baseband.

Matt

6
  1. What is range of the IF I can set its output to?

It has a fixed IF at 44Mhz I believe. A different version of the same tuner
module comes with 5.75Mhz IF. Matt, please correct me if I am wrong.

Yes, the shippingones have an IF of 44 MHz. The older ones were 5.75
MHz, but from the user’s point of view, it doesn’t matter. You don’t
need to know the IF.

Matt

7

ok… so i guess it is the passband sampling principle used here…

Do you still supply the MICROTUNE MT4937 module or some other ones?

Prasanna

8

Prasanna R. wrote:

If IF is at 44MHz, is it further downconverted(to around 5-15MHz)
before being fed to the ADC? I just want to know this out of
curiosity. Pls let me know.

This is why I publish schematics. If you look at it you will see that
the output of the tuner goes straight to the ADC.

Matt