the higher of two adjacent 540A frequencies whose harmonics pro-
duce zero-beat indications; f2 is the lower frequency. To use the
nomograph, locate two adjacent fundamental frequencies which
zero-beat with the unknown input signal. Find the higher of these
two frequencies in the left hand column, the lower in the center
column; place a straight-edge across these two points. The point
where the straight-edge intersects the right-hand column is the
number of the harmonic which beats with fx when the 540A is
tuned to fl. Multiply fl by the harmonic number to obtain the fre-
quency of the input signal (fx). -
In all of the following operating procedures the @ 524B Elec-
tronic Counter is used to measure the fundamental frequency of
the Transfer Oscillator. The fundamental frequency can be read
from the tuning dial on the 540A to an accuracy of 1/2% or better
and can be used in the equations given above to find unknown fre-
quencies below approximately 2000 megacycles. Above this fre -
quency it is necessary to use the Electronic Counter to rkad the
fundamental frequency with sufficient accuracy for the above
equations. However, unknown frequencies above 2000 megacycles
can be measured to 1/27' accuracy by reading the fundamental
frequency directly from the 540A tuning dial, if the number of the
harmonic which produces the beat-frequency has already been
de te r mine d.
CAUTION
Use care with large input signal levels. Use the
input attenuator so that under no conditions will
more than 1/2 watt average power or 50 volts
peak be applied to the ATTENUATOR or MIXER
INPUT jacks. Greater power or voltage levels
can damage the attenuator or oscillator probes.
J
2 -3 |
ACEC
