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Programmer’s Guide Page 64 of 66
Extra
Type
300 / sampInterval + 98
digitizers with 1 GS/s maximum sampling rates
300 / sampInterval + 194
digitizers with 2 GS/s maximum sampling rates or DC271-FAMILY
instruments set for a combine channel mode allowing 2 GS/s
300 / sampInterval + 386
DC271-FAMILY instruments set for a 4 GS/s combine channel mode
5. The copying time Cpy per 8-bit sample is ~ (5 s) / (Pentium CPU speed in MHz).
Thus, for a 250 MHz Pentium Cpy is ~ 0.02 s, and for a 500 MHz Pentium it is ~ 0.01 s.
Benchmarks were run on 266 and 550 MHz Pentiums, running under Windows 98 and NT. The observed transfer
times agreed with the formula within better than 20%.
dataType=3:
Add the conversion time T
3
for conversion from ADC codes to Volts, to T
2
or T
1
respectively:
ConvNMT
3
where Conv is the conversion time per sample in microseconds. It is ~ (35 s) / (Pentium CPU speed in
MHz). Thus, for a 250 MHz Pentium Conv is ~ 0.14 s, and for a 500 MHz Pentium ~ 0.07 s.
4.2. Examples
(A) DP210 in a 800 MHz Pentium:
Transferring single records of 100'000 samples, recorded at 2 GS/s:
672192480125.35.62
00625.001.00001001
ExtraOvhdOvhd
CpyXfrNM
bufferDMA
sXfrNMOvhdMT
DMA
106310005.62
1
s
CpyNMXfrExtraNMOvhdMOvhdT
bufferDMA
169800625.000010001.0672100125.35.62
2
It is therefore more favorable to use the function AcqrsD1_readData for readMode = 0.
Transferring 100 segments of 1000 samples, recorded at 2 GS/s:
672192480125.35.62
00625.001.00001100
ExtraOvhdOvhd
CpyXfrNM
bufferDMA
sXfrNMOvhdMT
DMA
725001.010001005.62100
1
s
CpyNMXfrExtraNMOvhdMOvhdT
bufferDMA
267200625.0000110001.06721100125.31005.62
2
The function AcqrsD1_readData for readMode = 1 (ReadModeSeqW) is about 2.7 times faster.