Centrad GF266 Manuel D'instructions page 27

MODULATION (Modul.)
Press the Modul. button [14]. Select the modulation schemes using the thumbwheel switch [17] and the Valid button
[15]. The following modulation schemes are available: Linear Sweep, Logarithmic Sweep, internal and external
Amplitude Modulation, internal and external Frequency Modulation, internal and external FSK, and internal and external
PSK.
Linear sweep (lin swp)
When linear sweep is selected, "START" is displayed, and the cursor positions itself below the frequency.
Set the start frequency using the thumbwheel switch [17] and arrows [16] and [18], then press Valid [15]; "STOP"
is displayed, and the cursor positions itself below the frequency.
Set the stop frequency using the thumbwheel switch [17] and arrows [16] and [18], then press Valid [15]; "RATE
value" is displayed, and the cursor positions itself under the time in seconds.
Set the time using the thumbwheel switch [17], then press Valid [15]; a star is displayed between the frequency
and function. From this time on, the output signal is swept linearily between the two selected frequencies at the
set rate.
The ramp start pulse is available on the IN/OUT VCF BNC socket [20].
To quit the modulation function, press Modul. (Stop Mod.) button [14].
Logarithmic sweep (log swp)
Refer to the procedure for linear sweep (above).
The output signal is swept logarithmically between the two selected frequencies at the set rate.
The ramp start pulse is available on the IN/OUT VCF BNC socket [20].
To quit the modulation function, press Modul. (Stop Mod.) button [14].
Internal amplitude modulation (int am)
After selection, "DEPTH value" is displayed.
Adjust the modulation depth using the thumbwheel switch [17], then press Valid [15].
A star is displayed between the frequency and function. From this time on, the output signal is amplitude-modulated
at a frequency of 800 Hz to the set depth.
To quit the modulation function, press Modul. (Stop Mod.) button [14].
External amplitude modulation (ext am)
After selection, a star is displayed between the frequency and function.
From this time on, the output signal is amplitude-modulated by the VCF input signal [20].
The depth depends on the input voltage; 1Vrms corresponds to100%.
To quit the modulation function, press Modul. (Stop Mod.) button [14].
Internal frequency modulation (int fm)
After selection, "DEV" is displayed, and the cursor positions itself below the frequency.
Set the deviation frequency using the thumbwheel switch [17] and arrows [16] and [18], then press Valid [15].
A star is displayed between the frequency and function. From this time on, the output signal is frequency-modulated
at 800Hz with the set deviation on either side of the start frequency.
To quit the modulation function, press Modul. (Stop Mod.) button [14].
External frequency modulation (ext fm)
After selection, "DEV" is displayed, and the cursor positions itself below the frequency.
Set the deviation frequency using the thumbwheel switch [17] and arrows [16] and [18], then press Valid [15].
A star is displayed between the frequency and function. From this time on, the output signal is frequency-modulated
by the VCF input signal [20] with the set deviation on either side of the start frequency. To quit the modulation function,
press Modul. (Stop Mod.) button [14].
Internal FSK modulation (int fsk)
After selection, "FREQ2" is displayed, and the cursor positions itself below the frequency.
Set your second frequency using the thumbwheel switch [17] and arrows [16] and [18], then press Valid [15].
A star is displayed between the frequency and function. From this time on, the output signal switches from frequency 1
(start frequency) to frequency 2 (set frequency) at the modulation frequency (internal 800Hz).
To quit the modulation function, press Modul. (Stop Mod.) button [14].
External FSK modulation (ext fsk)
After selection, "FREQ2" is displayed, and the cursor positions itself below the frequency.
Set your second frequency using the thumbwheel switch [17] and arrows [16] and [18], then press Valid [15].
A star is displayed between the frequency and function. From this time on, the output signal switches from frequency 1
(start frequency) to frequency 2 (set frequency) at the rate of the VCF input signal [20] (TTL level).
To quit the modulation function, press Modul. (Stop Mod.) button [14].
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