Foxconn 7870 manual Setting Up the Receiver

2.3 Setting Up the Receiver

2.3Setting Up the Receiver

1. Place the 7870R Receiver in any of the 7180M Chassis, unless a 2040 RF Switch is installed. (See Figure 7 7180M Chassis Rear View on page 12.)

Note If a 2040 RF Switch(es) is being installed, then slots 2 and/or 5 of the 7180M are reserved for the switch(es).

2.Apply AC power to the chassis. The Power Supply’s LED should be lit.

3.Using an optical power meter, measure the optical power coming to the Receiver from the fiber optic cable. The power levels of the Receiver should be the power level measured at the Transmitter minus the fiber loss2.

Alternatively, use a DVM to measure the voltage at:

•pins J13-P9 through J13-P16 for the slot being measured (See Table 5 7870R Receiver Pinout on page 21 for details regarding J13 pinouts) (7180M Rackmount). The voltage level should be 1 V for each 1 mW measured at the Receiver input.

•at pin #5 of the 9 pin connector (standalone)

4.On the rear panel, connect the coax cable to the RF Output Connector.

5.Adjust the Gain Control Potentiometer to give the desired output power. Using a small screw driver, turn the potentiometer (located on the front panel) to increase or decrease the gain.

Notes

1.The potentiometer is 10 turn potentiometer.

•To increase the gain, turn the gain control clockwise.

•To decrease the gain, turn the gain control counterclockwise.

For more information see 2.6 Aligning the Fiber Optic Link on page15.

2. If the LED is not lit, see Chapter 4 Troubleshooting on page 25.

2.Fiber loss is defined as:

(attenuation/km x length (km) of the fiber optic cable) + (0.5 dB × number of connectors).

For example if a signal with an optical wavelength of 1310 nm is transmitted over a link 10 kilometers long which had two connectors the loss would be:

(0.4 dB/km × 10 km) + (0.5 dB × 2) = 5.0 dB

page 10 Document no. 93-005-35-C5