Motorola STARLINE SERIES Instructions d'exploitation télécharger pdf (Page 27)

3-6 Amplifier Setup

BLE*/* Installation and Operation Manual

The information in Table 3-2 is shown as a graph in Figure 3-2:

Figure 3-2

Frequency versus cable slope

-1

-2

-3

-4

-5

-6

-7

-8

-9

-10

-11

-12

100

150

200

250

300

350

400

450

500

550

600

650

700

750

800

870

Cable slope (dB)

Frequency (MHz)

SCS-10

SCS-9

SCS-8

SCS-7

SCS-6

SCS-5

SCS-4

SCS-3

SCS-2

SCS-1

Input and Midstage Pads

Install Model JXP-*B pads to attenuate the signal per system design drawings. Generally, this

consists of attenuating excessive input levels. You should pad the input to system levels for

unity gain. Select and install the specified pad in the socket labeled

JXP-IN on the chassis cover.

You can use the midstage pad (

JXP-MID) to adjust the gain level and achieve the gain

specification. Refer to Section 6, “Operating Tips,” for midstage padding information and

recommendations.

Flatness Control

The 8LDR/*/III circuit board includes flatness controls and a fixed cable equalizer for 870 MHz.

This equalizer, plus the contribution of the hybrid gain stages, produces approximately the dB

of slope indicated by the model number (8 dB of tilt with an 8LDR/8/III or 12 dB of tilt with an

8LDR/12/III).

You can adjust the LDR variable resistors and capacitors to flatten the response across the

operating band (marker 1 to marker 4 as illustrated in Figure 3-4). Use C1, C2, R1, and R2 on

the LDR board shown in Figure 3-3 for low-end flatness response (marker 1 to marker 2). The

low-end flatness controls compensate for the roll-off caused by the diplex filters. Adjust C3 and

R3 for a flat response across the mid-band (between marker 2 and 3). Adjust C7, C8, and R8 for

a flat response across the band (marker 1 to marker 4). Adjust C6 for maximum gain at the high

end (marker 3 to marker 4).

 C1 produces a peak that is centered just below the lowest forward frequency and varied in

amplitude by R1.

 C2 produces a peak that is centered approximately 50 MHz above the lowest forward

frequency and varied in amplitude by R2.

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Motorola STARLINE SERIES Instructions d'exploitation Page 27

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