Operation - TTI TG550 Manual De Instrucciones

Switching On
Switch on the generator using the ON/OFF switch on the rear panel. To fully disconnect from the
AC supply unplug the mains cord from the back of the instrument or switch off at the AC supply
outlet; make sure that the means of disconnection is readily accessible. Disconnect from the AC
supply when not in use.
Ensure that the push-button switches in the SWEEP and AM/EXTERNAL COUNTER sections of
the control panel are all set to the
running mode. The display will show the frequency and peak-to-peak output amplitude with
appropriate range annunciators.
Frequency
Frequency Setting
Frequency is set by pressing the appropriate FREQUENCY RANGE push button and rotating the
calibrated FREQUENCY vernier; precise adjustments can be made using the FINE control. The
vernier controls provide a 1000:1 frequency change within each range. The auto-ranging meter
makes reciprocal frequency measurements down to 2·1Hz (to 0·21Hz on the 5Hz range); the
display update rate in this mode is 130ms or 1 waveform period, whichever is the longer. Below
these frequencies a fast measurement update rate is maintained by changing the measurement
method but accuracy is reduced, see Specification.
When SYMMETRY is switched ON the SYMMETRY control can be used to vary the duty cycle
from 1:10 to 10:1 to produce sawtooth and variable pulse-width waveforms. Optimum
performance of the SYMMETRY control is achieved on the top decade of each frequency range.
When SYMMETRY is selected SYM shows in the display and the generator frequency is divided
by 10; the display shows the correct frequency. The changeover in frequency measurement
method now happens at 0·21Hz on the 50Hz range and 0·42Hz on the 5Hz range.
Frequency Locking
The set frequency can be maintained precisely by using the FREQUENCY LOCK feature. Press
the LOCK button once to light the READY lamp. With READY lit set the required frequency in the
usual way, ensuring that the FREQUENCY RANGE has been selected such that the
FREQUENCY vernier control is within its top decade, i.e. between 0·5 and 5.
Press LOCK a second time to activate frequency locking; the LOCKED lamp will light to show that
frequency locking is operational. Frequency locking is disabled by pressing LOCK again (the
LOCKED lamp goes off) or by changing the frequency using the vernier or frequency range
switches.
Frequency Locking employs a 'measure-and-correct' technique; at low frequencies the time
between measurements is long (2s at 0·5Hz) and frequency stability may therefore be poorer.
Warning is given if frequency lock is about to be lost by flashing the LOCKED lamp; this may
occur with extreme variations of time and temperature which may cause the natural frequency of
the generator to drift outside the frequency locking control range.
Waveform
The output waveform shape is selected by depressing one of the three function buttons to give
sine, square or triangle. With all three switches out (accomplished by half-depressing any one)
the output will be a DC level only; this is useful as it permits input threshold testing of a circuit
without having to connect up an external DC supply.
10
position, i.e. set the generator to its normal, unmodulated,

Operation