User Manual

PicoScope 4000 Series Programmer's Guide 17
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4.8
Timebases
The API allows you to select one of 2
30
different timebases related to the maximum
sampling rate of the oscilloscope. The timebases allow slow enough sampling in block
mode to overlap the streaming sample intervals, so that you can make a smooth
transition between block mode and streaming mode.
For all PicoScope 4000 series scopes except the PicoScope 4262, the range of
timebase values is divided into "low" and "high" subranges, with the low subrange
specifying a power of 2 and the high subrange specifying a fraction of the clock
frequency. The PicoScope 4262 has a single range of timebases specifiying a power of
2.
Timebase (n)
Sampling interval (t)
PicoScope 4223
PicoScope 4224
PicoScope 4423
PicoScope 4424
PicoScope 4226
PicoScope 4227
PicoScope 4262
Low
2
n
/ 80,000,000
n=0:
12.5 ns
n=1:
25 ns
n=2:
50 ns
2
n
/ 250,000,000
n=0*:
4 ns
n=1:
8 ns
n=2:
16 ns
n=3:
32 ns
(n+1) / 10,000,000
n=0:
100 ns
n=1:
200 ns
n=2:
300 ns
...
n=2
30
-1:
~107 s
High
(n-1) / 20,000,000
n=3:
100 ns
n=4:
150 ns
n=5:
200 ns
...
n=2
30
-1:
~54 s
(n-2) / 31,250,000
n=4:
64 ns
n=5:
96 ns
n=6:
128 ns
...
n=2
30
-1:
~34 s
* PicoScope 4227 only
Applicability
Use ps4000GetTimebase API call.