Technical reference
28
Copyright 2005 Pico Technology Limited. All rights reserved.
PS3000044 1.4
3.4.9
Scaling
The PicoScope 3000 Series PC Oscilloscopes have resolutions that range from 8 bits to
12 bits, but the oscilloscope driver normalises all readings to 16 bits. This enables it to
take advantage of noise reduction from oversampling, when this is enabled. The following
table shows the relationship between the reading from the driver and the voltage of the
signal.
Reading
Voltage
-32 767
Minimum
0
Zero volts
32 767
Maximum
3.4.10
Signal generator
The PicoScope 3204/5/6 PC Oscilloscopes have a built-in signal generator which is set
using
. The output of the 3204 is a fixed-frequency square wave,
while the 3205 and 3206 can produce a selection of accurate frequencies from 100 Hz to
1 MHz, and the waveform can be set to sine, square or triangle and swept back and forth
in frequency. These options are selected under software control.
The signal generator output and external trigger input share the same connector, so
these two functions cannot be used at the same time. It is possible, however, to use the
output from the signal generator as a trigger.
3.4.11
Combining oscilloscopes
With PicoLog or your own program it is possible to collect data using up to four
PicoScope 3000 Series PC Oscilloscopes at the same time. Each oscilloscope must be
connected to a separate USB port. If a USB hub is used it must be a powered hub. The
function returns a handle to an oscilloscope. All of the other
functions require this handle for oscilloscope identification. For example, to collect data
from two oscilloscopes at the same time:
handle1 = ps3000_open ()
handle2 = ps3000_open ()
ps3000_set_channel (handle1)
... set up unit 1
ps3000_run(handle1)
ps3000_set_channel (handle2)
... set up unit 2
ps3000_run(handle2)
ready = FALSE
while not ready
ready = ps3000_ready (handle1)
ready &= ps3000_ready (handle2)
ps3000_get_values(handle1)
ps3000_get_values(handle2)
Note: It is not possible to synchronise the collection of data between oscilloscopes that
are being used in combination.
