Motorola SSETM 5000 - Manual (Page 77)

6881094C12-A November 11, 2004
Radio Alignment Procedures: Transmitter Alignments 5-7
5.5.4 Transmit Deviation Balance Alignment
This alignment procedure balances the modulation contributions of the low- and high-frequency
portions of a baseband signal. Proper alignment is critical to the operation of signalling schemes that
have very low frequency components (for example, PL) and could result in distorted waveforms if
improperly adjusted.
This procedure needs to be performed at multiple frequencies to allow for proper alignment across
the entire RF band. The RF band is divided into frequency zones with a calibration point (value) in
each zone.
NOTE: This alignment is required after replacing (or servicing) the VOCON board or the transceiver
board.
To align transmit deviation balance:
1. Select the TX Deviation Balance alignment screen. The screen indicates the transmit
frequencies to be used. See Figure 5-8 on page 5-7 .
2. Left-click the desired frequency field (starting with the highest frequency shown).
3. Left-click the PTT Toggle button on the screen to make the radio transmit. The screen
indicates whether the radio is transmitting.
4. Left-click the PTT Tone: Low button.
5. Measure the transmitted signal deviation of the radio with your communications system
analyzer.
6. Left-click the PTT Tone: High button.
7. Adjust the softpot value until the measured deviation, when using the High Tone, is as close
as possible to that observed when using the Low Tone.
Figure 5-8. Transmit Deviation Balance Alignment Screen