Hi 

I have the following flowgraph:
Noise source  ->  Throttle  ->   Stream to vector (Num items=1024)  -> 
FFT (FFT size=1024)  ->  Complex to mag^2  ->  Moving average  ->  
QT GUI vector sink
In 'Moving average' the parameters are:
Length = n_average
Scale = 1.0 / n_average
Max iter = 4000Length of vectors = 1024
To give a value for the parameter 'n_average' I have a 'QT GUI Range', with the 
following parameters:
ID = n_average
Default value = 9Start = 2Stop = 10 
Step = 1
If the 'Default value' above is 8, 9 or 10, I can change the value of 
'n_average' to any value between 2-10 when the flowgraph is running, and 
everything works fine. 

However, if the 'Default value' above is between 2-7, then always when I change 
the value of 'n_average' to 9, the flowgraph freezes (GUI vector sink is not 
updated anymore). There are no error messages. 

If I change the value of the 'Stop' parameter to 100, the same happens when 
'n_average' is changed to 9, but if I change 'n_average' to e.g. 62, I get an 
error message like
'gr::log :ERROR: block_executor - sched: <block moving_average (5)> is 
requesting more input data  than we can provide.  

ninput_items_required = 62  max_possible_items_available = 15  If this is a 
filter, consider reducing the number of taps.'


I am using Gnu Radio Companion version 3.9.5.0 (Python 3.8.10) in Ubuntu 
20.04.4 LTS. 
GRC has been installed by using PPA installation. 

cheers, Kimmo 




 

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