Theory of Operation: Main Board 3-7
3.1.1 Interconnections
This section describes the various interconnections for the main board.
3.1.1.1 Battery Connector M101
Battery connector M101 solders to the transceiver printed circuit board. The connector has 5 gold
plated contacts that mate with the battery, two contacts for positive, two for negative and one for the
Dig_Battery_Data. Signal descriptions are in Table 3-1.
3.1.1.2 Power Conditioning Components
DC power-conditioning components include zener diodes, capacitors, ferrite beads, a power
inductor, and the fuse. Diodes VR200 and VR101 provide over-voltage protection. Ferrite beads
(designated E, etc.) and capacitors suppress electromagnetic interference from the main board.
The power-line filter consisting of L200, C202, and C203 suppresses digital noise from the controller
board switching power supplies that could degrade the transmitter spectral purity.
Ground clips M103, M104 and M105 make contact between the main board ground and the radio
chassis. The chassis connection is a necessary electrical reference point to complete the antenna
circuit path. Shields SH1 through SH17 appear on the schematic to show their connection to ground.
Table 3-1. Battery Connector J3
Pin No. Signal Description
1 DC_BATT Battery positive terminal, nominally 7.5 Vdc
2 Dig_Battery_Data Battery status, from battery to controller
3 Ground Battery negative terminal, tied to PCB ground
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