SYNC Function
Function Generators
X -
49
SYNC Synchronisation Function (GX 320 only, contd.)
Thus when you programme a frequency of 100 Hz, the programmed value is:
ENT((100*2
28
)/10
7
+ 0.5) = 2684 which is the equivalent of a frequency of
99.987 Hz (obtained by reverse calculation).
If you wish to programme a synchronous n*100 Hz multiple frequency you must
enter a frequency which results in a DDS programmed value of n*2684, or a
true frequency equal to n*99.987 Hz.
In our example we will generate a square 100 Hz signal using its first three
harmonics: 3 sinusoids with a frequency of 100 Hz, 300 Hz and 500 Hz and an
amplitude of A, A/3 and A/5.
For this example 3 GX 320 generators are needed:
-
one Master: on which the SINE waveform is selected, amplitude 20 Vpp,
a null offset, a null phase and a frequency of 100 Hz
(or 99.987 Hz).
-
Slave 1: on which the SINE waveform is selected, amplitude 6.7 V, a null
offset, a null phase and a frequency of 3*99.987 = 299.96 Hz.
-
Slave 2: on which the SINE waveform is selected, amplitude 4 V, a null
offset, a null phase and a frequency of 5*99.987 = 499.93 Hz.
Connect the generators as shown in the Connections paragraph, activate the
slave outputs and then the master output (to ensure synchronisation do a
master MAIN OUT OFF and then ON).
On the oscilloscope connect the device MAIN OUT (respectively Master, Slave1
and Slave 2) outputs on channels 1, 2, 3.
Select the same sensitivity of 5 V/div. on each channel (choose the weakest
frequency signal as trigger: channel 1).
On channel 4 carry out the sum of Ch Ch Channel3, and
observe the result:
A square signal forms: the higher the number of odd harmonics the better the
signal quality obtained.