Boonton 9240 RF Voltmeter - Manual (Page 44)

Boonton 9240 Series RF Voltmeter
T I M E
C H 1 C H 2
S E C > 1 0 . 5 0 0 0 . 0 8
S A M P S 2 1 0 1 6
Figure 3-17. Averaging Time Display
3.3.5 Zero Key (single key press operation).
Zeroing should be performed when the unit is first warmed-up, a sensor has been changed or the instrument has drifted a
significant amount with respect to the signal level being measured. For large signals (measurements taken on range 4, 5, 6 or
7), this may be done once every several hours. For small signals, (measurements taken on range 0, 1, 2, or 3), zeroing should
be done before each measurement for optimum results. When zeroing is performed, the instrument calculates and stores zero
corrections for each range, and applies the corrections to subsequent measurements.
Assigning the <Zero> key as a single key press operation allows for a fast zeroing of the lowest hardware range to avoid the
longer zeroing process. When the Active Channel is measuring levels below approximately -50 dBm, and if the measurement
is settled, that is, if the filter is full, pressing the <Zero> key will take the displayed measurement as the zero reference. This
allows for faster and more acturate measurements of low level signals. If the measurement is not settled the complete zeroing
process of all ranges is performed.
The Zero menu is displayed by first pressing the <Menu> key followed by the <Zero> key. From there the user chooses the
the channel to perform the Zero operation on. The Zero menu invokes the command line as shown in Figure 3-18.
C H 1 C H 2
Z E R O <
Figure 3-18. Zero and Calibration Display
Table 3-8 Zero Menu Functions
Function Description
Parameters Defaults
ZERO
Performs zeroing of all hardware n/a n/a
ranges of the selected channel.
3.3.6 REL Level Key (single key press operation).
Often relative measurements are required especially when measuring system gains and losses. One key press of the
<Ref/Level> key makes this job easier and faster to perform. Simply connect the active channel’s sensor to the input signal of
the system under test. Press the <Ref/Level> key and the reference level is set! Next connect the sensor to the system output
and read the gain or loss directly from the reference level measurement.
The REF Level menu is displayed by first pressing the <Menu> key followed by the <REF Level> key. From there the user
may SET (entering a value ) or LOAD (use the current channel measurement ) the reference level on either channel.
Getting Started
3-18