Fast Signal Generator minimum output frequency?
Posted: Tue Oct 25, 2016 3:57 pm
I want to use one of the fast signal generator outputs on a red pitaya to create a 50Hz sawtooth ramp, which I would like to control from python. According to the SCPI commands list
http://archives.redpitaya.com/devel/SCP ... elease.pdf
the correct way to set the frequency is with where n is the source number and value is a frequency from 0Hz to 62.5MHz. With this in mind, and based on the RF output example on the RP site, I have written the following snippet as part of a python script:
With the frequency set to 7.65kHz, or above, everything works as expected, and if I hook up an oscilloscope to the output, as well as if I loop that output back to input 1 I can see the nice smooth sawtooth.
However as soon as I set the source frequency to anything less than the magic number of 7.65kHz (as I should be able to do according to the documentation, which says the RP outputs go down to DC) the signal disappears and I just get a flat line on my scope held at -10mV.
Does anyone know what mistake I'm making, or if this is a known issue, what is the workaround?
http://archives.redpitaya.com/devel/SCP ... elease.pdf
the correct way to set the frequency is with
Code: Select all
SOUR<n>:FREQ:FIX <value>Code: Select all
wave_form = 'SAWU'
freq = 7.65e3
ampl = 1
rp_s.tx_txt('GEN:RST')
rp_s.tx_txt('SOUR1:FUNC ' + str(wave_form).upper())
rp_s.tx_txt('SOUR1:FREQ:FIX ' + str(freq))
rp_s.tx_txt('SOUR1:VOLT ' + str(ampl))
#Enable output
rp_s.tx_txt('OUTPUT1:STATE ON')However as soon as I set the source frequency to anything less than the magic number of 7.65kHz (as I should be able to do according to the documentation, which says the RP outputs go down to DC) the signal disappears and I just get a flat line on my scope held at -10mV.
Does anyone know what mistake I'm making, or if this is a known issue, what is the workaround?