PicoScope 7 Software
Available on Windows, Mac and Linux
volatile signal phase
volatile signal phase
Hi,
I do an evaluation on the 4227. I use picoscop6, 2 Channels, no Trigger,
dc coupling, autorange, samplerate 1.5626Ms/s, 50ms acquisition time,
78130 samples per channel. I save the data in an .txt file, three columns:
time, channel 1, channel 2.
My analog signal is a 1.5Vpp sine, 200Hz from a hp signal Generator. The
signal is applied to two voltage dividers, 100R by 100R. The output signal
of the two voltage dividers is fed into the two channels of the 4227.
I analyze the two signals with a matlab script. I do a fft and calculate
the phase shift between the two signals.
I exspect a constant value, close to zero.
I do get ( 7 measurements ):
-8.6792e-004 rad, -8.2561e-004 rad, -8.8991e-004 rad, -8.9823e-004 rad,
-8.4968e-004 rad, -1.0148e-003 rad, -8.7078e-004 rad
One of the results is more than 10^-4 rad off the mean value, standard
deviation is close to 6e-5 rad.
That is to much for the anticipated use.
Questions:
Do you see any flaws in the setup?
Faulty software setup?
How do I get a more constant phase delay between the channels?
The 4227 does a multiplexing, using one ADC for two channels?
Are there any other pico products with two ADCs for two channels and
constant phase delay between the channels?
Second observation:
The recorded sample timestamps from the file are not equally spaced,
though the 4227 uses uniform sampling ?! Could this be the problem?
thank you for reading
Cheers
Detlef
I do an evaluation on the 4227. I use picoscop6, 2 Channels, no Trigger,
dc coupling, autorange, samplerate 1.5626Ms/s, 50ms acquisition time,
78130 samples per channel. I save the data in an .txt file, three columns:
time, channel 1, channel 2.
My analog signal is a 1.5Vpp sine, 200Hz from a hp signal Generator. The
signal is applied to two voltage dividers, 100R by 100R. The output signal
of the two voltage dividers is fed into the two channels of the 4227.
I analyze the two signals with a matlab script. I do a fft and calculate
the phase shift between the two signals.
I exspect a constant value, close to zero.
I do get ( 7 measurements ):
-8.6792e-004 rad, -8.2561e-004 rad, -8.8991e-004 rad, -8.9823e-004 rad,
-8.4968e-004 rad, -1.0148e-003 rad, -8.7078e-004 rad
One of the results is more than 10^-4 rad off the mean value, standard
deviation is close to 6e-5 rad.
That is to much for the anticipated use.
Questions:
Do you see any flaws in the setup?
Faulty software setup?
How do I get a more constant phase delay between the channels?
The 4227 does a multiplexing, using one ADC for two channels?
Are there any other pico products with two ADCs for two channels and
constant phase delay between the channels?
Second observation:
The recorded sample timestamps from the file are not equally spaced,
though the 4227 uses uniform sampling ?! Could this be the problem?
thank you for reading
Cheers
Detlef
Re: volatile signal phase
Can I ask you to submit this question to support@picotech.com with a copy of the text file data you have collected.
Martyn
Technical Support Manager
Technical Support Manager