Agilent Technologies 22A, 54621D, 24A, 42A, 54621A, 41A manual Counter, Duty Cycle, Frequency, Period

Making Measurements

Making time measurements automatically

Measurement definitions

Counter

The Counter measurement counts trigger level crossings at the selected trigger slope and displays the results in Hz. The gate time for the measurement is automatically adjusted to be 100 ms or twice the current time window, which ever is longer, up to 1 second. Any channel except Math may be selected for the source. Only one Counter measurement may be displayed at a time.

The Y cursor shows the edge threshold level used in the measurement.

The Counter measurement can measure frequencies up to 125 MHz. The minimum frequency supported is 1/(2 X gate time).

Duty Cycle

The duty cycle of a repetitive pulse train is the ratio of the positive pulse width to the period, expressed as a percentage. The X cursors show the time period being measured. The Y cursor shows the 50% point.

+ Width

Duty cycle = ------------------- X 100

Period

Frequency

Frequency is defined as 1/Period. Period is defined as the time between the 50% threshold crossings of two consecutive, like-polarity edges. A 50% crossing must also travel through the 10% and 90% levels which eliminates runt pulses. The X cursors show what portion of the waveform is being measured. The Y cursor shows the 50% point.

Period

Period is the time period of the complete waveform cycle. The time is measured between the 50% points of two consecutive, like-polarity edges. A 50% crossing must also travel through the 10% and 90% levels which eliminates runt pulses. The X cursors show what portion of the waveform is being measured. The Y cursor shows the 50% point.

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