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trigger instability and noise on measurements

Posted: Fri Jul 31, 2015 5:08 pm
by miguelgarcia
Hello

I'm here because I'm getting absolutely abnormal measurements ( at least on my point of view)
from my Red Pitaya, received 3 days before.

I will ask you if you could first read my descriptions bellow and then take a look at:

https://www.youtube.com/playlist?list=P ... IqpxMAVpLC

This is a link to videos about my measurements for several frequencies, for a 9Vdc battery and for a measurement with probes grounded.


DESCRIPTION of problems encountered:


1-

Trigger problems when measured from RP generator and visualized on RP,using the Generator and Oscilloscope application.

Most of the signals have an unstable visualization (or generation) , when they would be perfectly stable.

Please note this happens on both 1x and 10x sophistical probe settings (with the correspondent probe attenuation settings on software)

Video names: all of them started by a frequency number.

SETTINGS

OSCILLOSCOPE

source - channel 1
mode - normal
edge - rising
level - 0

probe attenuation - 1x
gain setting - LV

GENERATOR
signal type -sine
amplitude 2Vpp
frequency - "several for the videos"
DC offset - 0V trigger
mode - continuous



2-

Extreme noise when measuring a 9Vdc Battery,
which should be, by far, really much more close to zero.

Video name: 9V batery

Please note this happens on both 1x and 10x sophistical probe settings (with the correspondent probe attenuation settings on software)

SETTINGS

OSCILLOSCOPE
trigger:
source - channel 1
mode - auto
edge - rising

probe attenuation - 1x
gain setting - HV



3-

Extreme noise when measuring with the probes grounded,
which should be, by far, really much more close to zero.


Video name: both inputs grounded

Please note this happens on both 1x and 10x sophistical probe settings (with the correspondent probe attenuation settings on software)

SETTINGS

OSCILLOSCOPE
trigger:
source - channel 1
mode - auto
edge - rising

probe attenuation - 1x
gain setting - HV



-----------------------------------------------------------

MY PROBE SPECIFICATIONS

NOTE: Probes are compensated through their trimmer

modelHP-3060
Position x10
Attenuation Ratio 10:1
Bandwidth DC to 60MHz
Rise Time 5.8nS
Input Resistance 10MΩ when used with oscilloscopes which have 1MΩ input.
Input Capacitance Approx. 18 pF
Compensation Range 10 to 35 pF
Working Voltage 600V DC incl. peak AC derating with frequency.


Position x1
Attenuation Ratio 1:1
Bandwidth DC to 6MHz
Rise Time 58nS
Input Resistance 1MΩ (Oscilloscope Input Resistance)
Input Capacitance 91 pF Plus oscilloscope capacitance.
Working Voltage 600V DC incl. peak AC derating with frequency.


Lots of thanks advance for anyone who could emit a valid opinion about this ,

Miguel Garcia