BRUEL & KJAER 2006 - RF Voltage Measurements

ment is now adjusted to the correct reference, and RF measurements
can be carried out.
RF Voltage Measurements.
1. Set the VOLTAGE RANGE switch to its "50 mV'' position.
Note: If the RF Voltage to be measured is considered higher than 50 m V
the attenuator should be appliPd to the Input Probe.
2. Select BANDWIDTH, Wide or Narrow. In the FREQUENCY RANGE I
(o.l-6 MHz) use only "Narrow" for precise measurements.
3. Set the FREQUENCY RANGE switch to the desired range, and with the
TUNING knob tune to the signal frequency. If no signal, then;
4. Turn the VOLTAGE RANGE switch anticlockwise until a suitable de-
flection is obtained on the RF -meter.
5. Fine adjust the frequency TUNING knob for maximum deflection on
the meter. The LS AND MOD. ADJ. knob should be turned up when
tuning is carried out to aid the identification of the signal. The RF
voltage can now be read off the meter in conjunction with the VOLTAGE
RANGE switch.
Due to the untuned input circuit, a signal applied to the Heterodyne Volt-
meter will give a deflection on the meter for two different settings on the
frequency scale. The freqeuncy difference between the two settings will be
4654-4-o
Fig .. ~.1. Det er mination of an unknown frequency.
Equal RF-voltage readings at 122.u M l-Iz and 100 M liz
e.g. Signal frequency: 122.6 MHz.
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