Fluke PM-3384B Input filtering, Input impedance, Input polarity, Vertical range and offset

3 - 40 USING THE COMBISCOPE INSTRUMENTS

3.7.2Input filtering

The INPut:FILTer command allows you to turn the common low-pass filter (bandwidth limiter) on or off for all input channels at the same time. The cutoff frequency is fixed at 20 MHz. After a *RST command, the filter is turned off.

PROGRAM EXAMPLE:

CALL Send(0, 8,	"INPut:FILTer ON", 1)	’Turns the filter on
CALL Send(0, 8,	"INPut:FILTer:FREQuency?", 1) ’Requests for the filter frequency
response$ = " "
CALL Receive(0,	8, response$, 256)	’Reads the filter frequency
PRINT "Filter freq. = "; response$		’Prints: Filter freq. = 2.00E+07

3.7.3Input impedance

The INPut<n>:IMPedance command allows you to specify the input impedance low (50 Ω) or high (1 MΩ) for each input channel separately. After a *RST command, the impedance of each input channel is 1 MΩ.

PROGRAM EXAMPLE:

CALL Send(0, 8, "INPut4:IMPedance 50", 1) ’Sets channel 4 impedance at 50Ω

3.7.4Input polarity

The INPut<n>:POLarity command allows you to set the polarity of the signal on the input channel 2 and 4. The polarity can be set to NORMal (default) or INVerted (inverted signal).

PROGRAM EXAMPLE:

CALL Send(0, 8, "INPut2:POLarity NORMal", 1) ’Sets INV CH2 off

CALL Send(0, 8, "INPut4:POLarity INVerted", 1) ’Sets INV CH4 on

3.7.5Vertical range and offset

The SENSe:VOLTage<n>:RANGe:PTPeak command allows you to specify the peak-to-peak range of the signal acquisition over all 8 divisions of the display screen for each input channel separately. From this peak-to-peak value the vertical sensitivity per division is calculated as follows:

<vertical_sensitivity> = <peak-to-peak> / 8.

After a *RST command, the peak-to-peak value is set at 1.6V for channel 1, which complies to a vertical sensitivity of 200 mV.