Motorola R-2200 Operator's Manual page 40

4. Adjust the attenuator as in step A-3 above, to
produce an adequate signal level to the service
monitor's receiver.
5. Adjust the transmitter and follow the same pro-
cedure outlined in steps A-5 through A-7 above,
to measure frequency and deviation.
6. This same method may be used to verify fre-
quency and deviation of a remotely located trans-
mitter by reducing the attenuator setting to fully
realize the 1.5uV (10 dB SINAD) sensitivity of
the service monitor's "of-the-air" monitor func-
tion. To insure sufficient measurement accuracy
however, make sure the Monitor receiver is fully
quieted as in step A-3 above.
C. Harmonic Power Measurement (R-2400)
1. Referring to Figure 5.6, insert a fixed power at-
tenuator between the RF output connector of the
transmitter and the "Antenna" port of the
R-2400. The power rating of this attenuator must
be at least equal to the rating of the transmitter,
and a minimum of 30 dB attenuation. The input
power to the antenna port must not exceed 0.5
watt.
2. Set the "Function" switch to "Sens Mon/ Anlzr
On" and enter the carrier frequency, as before.
3. Observing the CAUTION above, with a fixed at-
tenuator in series, key the transmitter and set the
step attenuator for a peak indication on the spec-
trum analyzer between the REF and -10 dB
graticules. Note the displayed level and the step
position in dB. De-key the transmitter.
4. Enter the frequency of the harmonic or spurious
signal of interest. Key the transmitter and
observe the level of the signal on the spectrum
analyzer, adjust the step attenuator if necessary,
should the signal be too low to observe. Confirm
that the signal changes 10 dB for a 10 dB change
in the step attenuator setting (See notes on page
5.2). Note the level of the signal and the step at-
tenuator setting, in dB. De-key the transmitter.
5. Compute the level difference between the carrier
and the spur /harmonic as follows:
A. Let "REF"= 0 dB, and step position is a nega-
tive number.
B. PC= displayed level of carrier-(step) ie.:
-3 dB-(-50 dB)= +47 dB
C. P1 =displayed level of spur-(step) ie.:
-22 dB-( -30 dB)= + 8 dB
D. The relative difference between the carrier and
spur/harmonic levels is P diff=PC-P1 =47-8
=39 dB.
5-6
D
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TRANSMITTER
FIGURE 5. 7- TRANSMITTER AUDIO FREQUENCY
RESPONSE
D
Mon 1 !54 .:5:50 MHz
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FIGURE 5.8- TRANSMITTER AUDIO DISTORTION
SETUP