So what is the official noise spec??????

Post any questions you may have about our current range of oscilloscopes
Post Reply
dmalan
User
User
Posts: 3
Joined: Tue Nov 21, 2006 9:21 am

So what is the official noise spec??????

Post by dmalan »

Hi,
I bought three Picoscope 3424 units recently. I was quite dismayed to notice that the residual noise of these units is quite big. On all of my units there seems to be random noise with amplitudes ranging between 5 and 8 resolution steps (Inputs shorted). With the units set to +-5 volt range, these steps are 2.44mV each so the noise has an approximate vallue of up to 20mV P-P. 8 Resolution steps represents 3 bits of the available 12, effectively reducing the instrument to a 9 bit device.
I tried to find some noise specs for these units in the product specification but could not find any.
Any comments?
NM

davidj
Site Admin
Site Admin
Posts: 43
Joined: Wed Oct 11, 2006 8:50 am
Location: St. Neots, Cambs, UK

Post by davidj »

Hi
The noise free resolution of any oscilloscope depends on the voltage range selected, sampling rate, memory depth used etc etc so is almost impossible to quote.

Using the scope and specifications you list we got about 7mV RMS of noise on the 5V range. If you wish to reduce the noise / increase the resolution then this can easily be done by oversampling. Details of how to do this can be found in the following technical tips section of the web site http://www.picotech.com/technical_tips.html
Regards,
David

Post Reply