User's Manual

Chapter 3 Controls & Indicators

Transmitter/Receiver Status Indicators:

The MMI is equipped with eight receivers and one transmitter. All of these devices use

phase-locked-loops (PLL’s) to control each frequency with a high degree of accuracy.

The PLL’s also allow both transmitter and receiver frequencies to be easily changed with

software in real time. Many of the status LED’s to be described below display PLL

programming status. Since each PLL is software programmable, it is important to be able

to instantly verify if a particular one has been programmed correctly. It is possible to

improperly, either intentionally or accidentally, program a PLL to a frequency where the

transmitter or receiver is not able to operate correctly. In this case, the PLL OK LED

would be turned off.

There are four receiver boards with two receivers on each board. These cards and their

locations are displayed in figure 3. Each receiver channel has two LED’s to display

programming and data status. Each green LED on the receiver boards is used to verify

that particular channel has been programmed to a valid frequency. The green LED’s

should be illuminated at all times during operation except for approximately 7 seconds

after MMI power is initially applied. During this time, the LED’s may be either on or off

randomly. During normal operation, all green LED’s should be illuminated. The red

LED’s will flash any time a particular channel is receiving valid data, visually verifying

that the receiver is working properly.

There is one transmitter board in the MMI and its location is shown in figure 3. The

transmitter has three LED’s used to display its status. The Power OK LED should be

illuminated any time the MMI is powered. As with the receiver PLL OK LED, the

transmitter PLL OK LED should be illuminated at all times. The TX On LED displays

whether the transmitter has been enabled by the software. Referring to figure 2, anytime

the TX On LED is illuminated, the RF Amp Enabled LED should be illuminated as well.

This verifies that the RF amplifier is operating.

Figure 3.

Transmitter/

Receiver Status

Indicators

Receiver Cards

#1&2 #3&4 #5&6 #7&8

Transmitter

Card

PLL OK

Data

PLL OK

Data

Power OK

PLL OK

ot used

TX On

CH1 CH3 CH5 CH7

CH2 CH4 CH6 CH8