BRUEL & KJAER 1018 Instructions And Applications page 18

Fig. 6. Frequency Dial of Type 1018.
the screw Sn counter-clockwise until it is stopped by the contact arm
of the microswitch. Fasten Sn in this position.
3. Turn the "Oscillator Frequency Dial" clockwise until the pointer points
at the highest frequency at which measurements are to be taken. Then
move the screw Sb clockwise until it is stopped by the contact arm
of the microswitch. Fasten Sb in this position.
4. Set the "Scanning Speed" knob to the desired value, and switch on the
frequency sweep by turning the " Scanning Speed Multiplier" to "xi "
(or "x0.1 ", depending upon the speed chosen for the sweep).
The selected frequency range will now be swept automatically. When the
preset limits of the range are reached, the rotation of the motor is reversed
and the same frequency range will be traversed with the same speed, but
in the opposite direction.
The correct setting of the "Scanning Speed" knob is easily calculated: If
it is desired to scan the frequency range f1 - f2 - f1 in T minutes lhe
settings of the "Scanning Speed" knob is found from
S =
where d2 and d1 are the degrees corresponding to the frequencies f2 and
fr ,
respectively. These values can be read directly off the frequency dial. In
other words , the scanning speed is the total scanning range in degrees
divided by the desired scanning time.
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