Ametek 7280 Instruction Manual page 73

The controls on the Configuration menu operate as follows.
LINE FREQUENCY
This control is used to set the center frequency of the line frequency rejection filter,
and so should be set to the prevailing line frequency, i.e. 50 or 60 Hz.
NOISE MEASUREMENT
This control is used to configure the instrument for noise measurements. When
turned ON, the Main Display output displays (see section 5.3.01) are set as follows:
Display Position
1
2
3
4
The available output time constant is restricted to the values in the range 500 µs to
10 ms inclusive, since it is only at these values that the noise measurements are
calibrated, and the Synchronous time constant control (section 5.3.06) is turned off
The output filter slope is also restricted to either 6 or 12 dB/octave.
When the noise measurement control is turned OFF then the instrument is configured
for normal lock-in amplifier operation.
NOISE BUFFER LENGTH
This control, which is only active when the above NOISE MEASUREMENT control is
turned ON, sets the averaging time of the buffer used to determine the mean value of
the output signal when making noise measurements. Settings of Off, 1 s, 2 s, 3 s and
4 s can set using the adjacent
The operation of this control is described in more detail in section 3.3.16
Firmware version X.X
This line, immediately under the menu title, gives the version number of the
instrument's operating firmware. The firmware in the instrument can be updated to
the latest revision by connecting it to a PC via the RS232 interface and running an
Update program.
Analog Outputs
Pressing a key adjacent to this item displays the Analog Outputs menu, which is used
to define which instrument outputs are converted to analog voltages and made
available at the CH1 and CH2 connectors on the rear panel. This menu is described
later in section 5.3.18
Options
The key gives access to the Options Menu, which is used to install firmware options
within the instrument. It is discussed later in section 5.3.19
Chapter 5, FRONT PANEL OPERATION
Displayed Output
Noise expressed in V/√Hz in large digits
Noise expressed in V/√Hz as a bar-graph
X output in expressed as a percentage of the full-scale
sensitivity as a bar-graph
Magnitude output (R) output in expressed as a
percentage of the full-scale sensitivity in large digits.
key.
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