Operating instructions

University of Saskatchewan
Electrical Engineering Laboratory Equipment Manual
To set the modulating frequency ( 10mHz to 10KHz, internal source only ), push
the Shift key and then the Freq key. Adjust the frequency.
The peak frequency deviation is the change in frequency, of the modulating
waveform, from the carrier frequency. Push the Shift and then the Level key.
Adjust the frequency deviation.
To disable the frequency modulation press the Shift key and then the FM key.
Agilent 33220A Function Generator / Arbitrary Waveform Generator
The 33220A is a direct digital synthesis generator. This generator has standard
waveforms such as: sine, square, triangle, ramp, pulse and noise. Arbitrary waveforms
can also be created. This generator can do frequency sweeps and different forms of
modulation. The generator can also be programmed over the remote interface. The
standard waveform functions are used in the laboratory classes.
This generator will limit the maximum and minimum values. These values will be
limited by the associated values you set or limits of the generator.
The function generator has a fixed output impedance of 50 ohms. You can
specify which load you are terminating the output into, 50 ohm or High Z. Incorrect
impedance matching between the source and the load will result in a magnitude output
which does not match the display value. The generator will output twice the magnitude
displayed on the generator, with the load termination on 50 ohms.
With the load termination setting on 50 ohms and a 50 ohm load on the output,
half the generator’s source voltage is across the generator’s internal output impedance
of 50 ohms and half across the 50 ohm load. The voltage drop across the 50 ohm load
matches the magnitude displayed on the generator.
With the load termination setting on 50 ohms and a high Z load, practically all of
the output voltage is across the load. The voltage across the high Z load is twice the
magnitude displayed on the function generator.
Set the load termination to High Z for a high Z load. The generator’s output
magnitude will match the magnitude displayed on the generator with the load
termination setting on High Z, provided the load is a high Z and not 50 ohms. The
voltage across the load will be half the display value, with a load termination of High Z
and a 50 ohm load. Most devices used in the Lab have a high input impedance.