[Discuss-gnuradio] QT GUI Bercurve Sink - confusion about number of block ports

[Tracie Perez]

Hi all,

If I open a new flow graph in GRC and select a QT GUI Bercurve Sink 
block, the default parameters create 16 ports (connections) on the 
block. The default in the "Num Curves" field is 1 and the default in the 
"esno" field is numpy.arange(0.0, 4.0, .5), which is 8 values. I'm not 
sure why there are 16 ports.

If you then change "Num Curves" to 2, the number of ports on the block 
changes to 32. Also, if you change the value of "esno" to a different 
range of values, it changes the number of ports. Is that on purpose? 
Should the specified number of esno values be related to the number of 
ports?

I would expect that the number of ports on this block is simply equal to 
the number of curves specified. i.e., 2 in the "num curves" field 
generates 2 ports on the block.

In fact, that is the behavior of the ber_curve_gen.grc example. However 
if you start from a new flowgraph, there's a different behavior.

Any clarification on this would be appreciated. I'm working with GNU 
Radio v. 3.7.9.1.

Thanks,
tracie