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T A K I N G
M E A S U R E M E N T S
2. Turn the marker off if it is currently on. Adjust the settings until your desired
signal is displayed, with a span narrow enough for your required accuracy. A 5
to 50 KHz span is ideal for many measurements.
3. Place your marker using the mouse (left-click) or the PEAK button.
4. Press the DELTA button. This freezes the location of the first marker's
REFERENCE point (e.g. 1R).
5. Move the marker by left-clicking inside the graticule then using the mouse
wheel to fine-tune the marker's position.
6. The differential measurement is displayed below the graticule.
If you want the marker to update automatically with each sweep, toggle "UPDATE
OFF" to "UPDATE ON"
3.1.4
Measuring Low Level Signals
To measure low-level signals, there are a few tricks to getting accurate readings. First
of all, set the internal electronic attenuator to 0 dB (click the ATTEN button). Then,
set your reference level to -40 dBm or lower. This internally selects the highest
sensitivity settings.
should give you better results. For frequencies above 500 KHz, the RF preamplifier
may be turned on to further reduce the noise floor. Video averaging may be required
for a stable amplitude reading.
3.1.5
Measurements Near DANL
The amplitude displayed is the sum of all energy present in the IF. This includes the
signal as well as noise and residual responses. Measurements of signals less than 10 dB
above the noise floor will have a measurable amplitude error due to the addition of
noise. To compensate for this, subtract the amplitude with no signal present (the
noise), in linear power units, from the amplitude with signal present, to calculate the
signal level. Please note that the measurement uncertainty will increase from this
process.
3.1.6
Capturing Pulsed or Intermittent Signals
To capture an intermittent signal of unknown frequency, MAX HOLD may be used.
If the duration of the signal is less than the displayed sweep time, turn off image
rejection to capture the signal. For very short signals, video bandwidth should be set to
maximum. Sweep Time may be turned to slow
3.2 Viewing Modulation
A signal's modulation envelope may be viewed or measured using ZERO SPAN. To
use zero span, follow these steps:
Using an external timebase and narrow span (1 KHz or less)
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