BNC 630 - Manual (Page 48)

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5.26 Voltage Controlled Oscillator (VCO) Mode
Introduction
The Voltage Controlled Oscillator mode allows the user to vary the output frequency between two specified frequencies using an
externally applied voltage. By applying a voltage between -5.0V and +5.0V to the External Modulation In connector (rear panel),
the output frequency can be adjusted between the Start and End frequency values. The control input bandwidth is DC to 35 KHz.
To enter this mode, press Mode, 4, 2
VCO Mode Parameters
The Voltage Controlled Oscillator mode has the following front panel display:
Figure 5.26-1: VCO mode display
1. Start Frequency
This is the output frequency when -5.0V is applied to the External Modulation In connector (rear panel). You may enter from 0 Hz
(DC) to 21.5000000 MHz in .01 Hz steps.
NOTE: You are not allowed to enter a start frequency that is greater than the end frequency.
2. End Frequency
This is the output frequency when +5.0V is applied to the External Modulation In connector (rear panel). You may enter from 0
Hz (DC) to 21.5000000 MHz in .01 Hz steps.
NOTE: You are not allowed to enter an end frequency that is less than the start frequency.
3. Level
In this field enter the output level, from 4 mVp-p to 10 Vp-p in 1 mV steps or from -44.0 dBm to +24.0 dBm in .1 dBm steps.
NOTE: The level specified is a 50 ohm LOADED level. This is the level of the signal which will appear across a 50 ohm load
connected to the SIG Out connector. Into an open circuit, the output swing will be twice the value entered.
Offset
You can enter an offset voltage for the output waveform. For more information on output offsets refer to section 4.4.
External Modulation In
(rear panel connector)
Apply the control voltage to this connector. For this mode, the input signal may be in the -5.0V to +5.0V range. Levels outside this
range will be clipped by limiting circuitry. *** Caution : Levels outside -25V to +25V may damage the 630.
VCO Start: 1,000.00 Hz
End: 20,000,000.00 Hz -10.0 dBm
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