Motorola STARLINE SERIES Instructions d'exploitation télécharger pdf (Page 32)

Amplifier Setup 3-11

BLE*/* Installation and Operation Manual

Position the drive control select jumper (Figure 2-8) temporarily in the MAN position and

perform the complete procedure described in Manual Gain Control if not already completed.

3 Position the drive control select jumper to AUTO.

4 Connect a signal-level meter to the FWD OUT test point and tune the meter to the high

band-edge carrier.

5 Turn the thermal level potentiometer on the TDU fully clockwise and then reduce to obtain

the level obtained in Step 9 under Manual Gain Control.

Automatic Drive Unit

The ADU operates by using surface acoustic wave (SAW) filters to select a pilot frequency and

then monitors the amplitude of this frequency. Any change in signal level is fed back to the Bode

equalizer. It is assumed that the encountered signal level changes are due to changes in cable

attenuation and hybrid output associated with a change in temperature. The Bode equalizer

then changes its insertion loss to maintain a constant output level. The ADU (illustrated in

Figure 3-6) maintains the most precise output level of the three available methods.

Figure 3-6

ADU

AUTOMATIC

DRIVE UNIT

ADU/ _______________

Pilot frequency

To set-up the ADU:

1 Position the drive control select jumper temporarily to the MAN position and perform the

complete procedure described in Manual Gain Control if not already completed.

2 Verify that the frequency stamped on the ADU control unit is the same as the system pilot

frequency. The pilot frequency is a CW or an available NTSC television channel not

scrambled using sync suppression and not a digital channel.

3 Position the drive control select jumper to AUTO.

4 Connect a signal-level meter to the FWD OUT test point and tune the meter to the high

band-edge carrier.

5 Turn the auto level control potentiometer (ADU) (illustrated in Figure 2-8) fully clockwise

and then reduce to obtain the level obtained in Step 9 under Manual Gain Control.

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Motorola STARLINE SERIES Instructions d'exploitation Page 32