[Discuss-gnuradio] Questions for 150/400MHz beacon RX development

[Mamoru Yamamoto]

Thank you for your kind help to my questions.
I am developing a satellite beacon receiver of 
150/400MHz.  Now I am receiving both signals by 
using Basic RX (150MHz) and FLEX400 (400MHz) boards.
I am happy so far.

I have some more questions for further development.

(1) File format
I record signals into files.  I want to read them 
for analysis.  What is the data format written/read 
by file_sink() / file_source()?  I am recording 
complex signals in the files.

(2) "O" "U" "u" "a" 
These characters appear on the screen when I run 
my program.  I understand they appear when data flow 
from USRP to PC is stopped or something.  I am curious 
what are the meaning of these characters.  Does faster 
PC help reducing such data flow troubles?

(3) Signal coherence .. (a)
I need to keep signal coherence between 150MHz and 400MHz.
I should run the FLEX400 board at the same timing to the 
USRP main board.  I found the following information URL
http://comsec.com/wiki?USRPClockingNotes
Is this instruction still valid?  I am using USRP ver4.

(4) Signal coherence .. (b)
I have one more question on the signal coherence.  In my 
program I keep the same sample speed and the same FIR filter 
for both 150MHz and 400MHz. (Sure I am using a "deinterleaver" 
to separate the signals.)  Can you guarantee signal coherence 
in the GNUradio data flow?

Regards,

----
Mamoru Yamamoto  address@hidden