Fluke PM6681R, PM6685R manual Switchbox, Prescaling, Sense Command Subsystem

Using the Subsystems

Sense Command

Subsystems

Depending on application, you can select different input channels and input charac- teristics.

￿Switchbox

In automatic test systems, it is difficult to swap BNC cables when you need to mea- sure on several measuring points. With PM6680B/1 you can select from three different basic inputs (A, B and E), on which the counter can measure directly without the need for external switching devices. With PM6685 you can select from two different basic inputs (A and E).

￿Prescaling

For all measuring functions except fre- quency, the maximum input A frequency is 160 MHz.

To extend the range for frequency mea- surements, PM6680B and PM6685 can divide (scale) the input A frequency by two, while PM6681 scales by four.

When using channel 1, the counter auto- matically selects this scaling factor when measuring FREQ A, giving 300 MHz max frequency for PM6681 and PM6685, and 225 MHz for PM6680B.

For all other measuring functions, and for frequency if you select negative slope, the counter does not divide the signal and the max repetition rate is 160 MHz.

Sense Command Subsystem 6-13