5520A
Operators Manual
4-58
4-52. Synchronizing the Calibrator using 10 MHz IN/OUT
You can synchronize one or more 5520A Calibrators using the 10 MHz IN and OUT
input/output on the rear panel. Example applications of this capability are connecting
two or more calibrators in parallel in the current output function to sum their outputs, or
using three calibrators to calibrate a three-phase power meter.
Another use for the 10 MHz IN reference input is to improve the frequency performance
of the 5520A by injecting a reference 10 MHz clock signal. That application is described
next.
4-53. Using an External 10 MHz Clock
The calibrator uses an internal 10 MHz clock signal as a reference for all ac functions.
Although this internal clock is very accurate and stable, you may have a lab standard that
you want to have govern the frequency performance of the calibrator. To apply an
external clock to the calibrator, you have two choices. You can make external reference
the power-up and reset default condition, or you can select external reference as a
volatile setting for the operating session only.
To make external reference the power-up and reset default setting, proceed as follows:
1. Connect a 10 MHz square wave signal of 5 V p-p (maximum) to the rear panel
10 MHz IN BNC connector.
2. Press the S key.
3. Press the following sequence of softkeys: INSTMT SETUP, OUTPUT SETUP,
φ & REF SETUP.
4. Press the REF CLK softkey to select “ext.”
5. Press the Pkey.
To use an external 10 MHz reference on a temporary (volatile) basis, proceed as follows:
1. Connect a 10 MHz square wave signal of 1 to 5 V p-p to the rear panel 10 MHz IN
BNC connector.
2. Press the S key.
3. Set the calibrator output to an ac voltage or current function.
4. Press the following sequence of softkeys: INSTMT SETUP, OUTPUT SETUP,
φ & REF SETUP.
5. Press the REF CLK softkey to select “ext.”
6. Press the Pkey.
4-54. Sourcing AC Current with Parallel-Connected 5520As
You can connect two or more 5520As to source current in parallel. This technique allows
you to source current greater than ±20 A. If you are sourcing ac current, you must
synchronize the calibrators in order to have their output currents in phase. Proceed as
follows to accomplish this:
1. With both 5520As in standby mode, make the connections as shown in Figure 4-16.
To Next Page
Loading...
