2.Specifying the Sample Count. The sample count (i.e. trigger count) is specified by the size parameter (50) of the CONFigure command. This is the most convenient way to specify the sample count since size is a required parameter of CONFigure. TRIGger:STARt:COUNt can be used to set/change the sample count without also changing the entire configuration with CONFigure.

3.Additional Information. Additional information on trigger sources and sample rates is found in Chapter 3 - "Understanding the Digitizer", and in Chapter 4 - "Command Reference".

Dual Rate Sampling

This program demonstrates:

how to set up the digitizer’s dual rate sampling function whereby pre-arm and post-arm readings are taken at different sample rates.

how level arming can be used with dual rate sampling

The digitizer pre-arm samples at 50 ns until the level of the input signal on channel 1 reaches 5V. At 5V, the digitizer is armed and post-arm samples at 10 ms.

DUALSAMP.C

*RST;*CLS

/* clear and reset the digitizer */

CONF1:ARR:VOLT (20),10,(@3)

/* set 20 readings, 10V range */

ARM:SOUR1 INT1

/* set arm source 1 for level arming */

ARM:SOUR2 HOLD

/* disable arm source 2 */

ARM:SLOP1 POS

/* arm on increasing input signal */

ARM:LEV1:POS 5

/* arm at 5V (10V range) */

SENS:SWE:OFFS:POIN -10

/* set 10 pre-arm readings */

TRIG:SOUR DTIM

/* set dual rate sampling */

TRIG:TIM1 50E-9

/* set sample rate for pre-arm readings */

TRIG:TIM2 10E-3

/* set sample rate for post-arm readings */

INIT

/* put digitizer in wait-for-arm state */

FETCH?

/* retrieve readings */

Comments 1. Dual Rate Sampling Periods. The dual rate sampling trigger source DTIMer uses the internal timer sources. Thus, one sample period must equal the reference period. In this program, the digitizer’s internal

20 MHz oscillator is the reference source. Therefore, one sample rate must be 50 ns (1 / 20 MHz).

Chapter 2

Using the Digitizer 55

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HP E1429A manual Dual Rate Sampling, Dualsamp.C, ARMSLOP1 POS, Senssweoffspoin, Trigsour Dtim