From a function generator into the LF-RX (maximum load)


#1

Hi All,

as i read in the documentation,
http://gnuradio.org/trac/attachment/wiki/UsrpFAQ/USRP_Documentation.pdf
Page 44, there is only a statement about maximum load at the Basic-RX.
(From a function generator directly into the input of the Basic-RX)

So i ask you,
is there a built-in safety to save the LF-RX from being damaged too?

Regards Markus


#2

Markus F. <feldmann_markus gmx.de> writes:

Hi All,

as i read in the documentation,
Is there additional documentation for the LF-RX
Daughterboard ?

Regards Markus


#3

On Fri, Feb 20, 2009 at 3:05 PM, feldmaus removed_email_address@domain.invalid
wrote:

If you look at the LFRX the input consists of AD813x fully differential
amplifier with unity gain and a input impedance of 50 ohm. I am not sure
if
there are diodes which limit the signal swing, maybe looking at the
schematics can help you with this.

From what I understand the LFRX and Basic-RX are very similar, so the
same
rules for safety apply. I have used 2V pk-pk voltages as input from a
signal
with a source impedance of 50 ohms without any problems. If your source
doesn’t have a 50 ohm source impedance, the DC voltage will be incorrect
by
about 106mV (there are some threads which discuss this issue in greater
detail).

Karthik


#4

Karthik <karthik1024 gmail.com> writes:

If you look at the LFRX the input consists of AD813x fully differential
amplifier with unity gain and a input impedance of 50 ohm. I am not sure if
there are diodes which limit the signal swing, maybe looking at the
schematics
can help you with this.
Where are the Schematics ?
From what I
understand the LFRX and Basic-RX are very similar, so the same rules
for safety apply.
I read that the Basic-RX has a Transformator which gives the
Safety.
But the LF-RX has no Transformator!

Regards Markus