DM588 Service Manual
4. Circuit Description
4.1.Schematic Circuit Diagram of Main Board
4.2.Tx Circuit
The TX circuit includes an RF power amplification circuit, a low pass filter circuit and an automatic
power control circuit.
RF Power Amplification Circuit
Transmitting signals TX VCO are buffered and amplified by the Q7, Q8, Q9 and then the pre-drive
amplifier Q18 to generate strong enough driving power signals, and then amplified by the last-stage
amplifier Q29. Then, impedance matching is finished at the output end of the last-stage amplifier
4
Summary of Contents for DM588
Page 142: ...DM588 Service Manual Figure 4 Top Layer Layout Drawing of Main Board B Board 139 ...
Page 143: ...DM588 Service Manual Figure 5 Bottom Layer Layout Drawing of Main Board B Board 140 ...
Page 144: ...DM588 Service Manual Figure 6 Top Layer Layout Drawing of Main Board D Board 141 ...
Page 145: ...DM588 Service Manual Figure 7 Bottom Layer Layout Drawing of Main Board D Board 142 ...
Page 147: ...DM588 Service Manual Figure 9 Top Layer Layout Drawing of LCD Board 144 ...
Page 148: ...DM588 Service Manual Figure 10 Bottom Layer Layout Drawing of LCD Board 145 ...
Page 150: ...DM588 Service Manual Figure 12 Top Layer Layout Drawing of Key Board 147 ...
Page 151: ...DM588 Service Manual Figure 13 Bottom Layer Layout Drawing of Key Board 148 ...