4 - 1SECTION 4 CIRCUIT DESCRIPTION4-1 RECEIVER CIRCUITSRF CIRCUITS• 118−174 MHzThe received signals from the antenna connector ANT-1(J1) are passed through two LPFs (L101, 104, 108, C342,346; L88, 92, 96, C318, 326, 330), then applied to the RFamplifier (Q37) via TX/RX switch (D75). The amplified signalsare passed through the RX switch (RL2), attenuator (D68)and tuned BPF (D55, 66), before being applied to anotherRF amplifier (Q33). The amplified signals are applied to the1st mixer (IC19) via the another tuned BPF (D41, 44) andRX switch (D38).While the diversity operation is activated, the receivedsignals are also input from ANT-2 (J2). The received signalsare passed through two LPFs (L103, 106, 109, C344, 348;L90, 93, 98, C319, 327, 348), antenna switch (D65, 72) andlimitter (D64, 67), then applied to the RF amplifier (Q39).The amplified signals are applied to the RX switch (RL2),and gone through the same process as the received signalsfrom ANT-1 (J1).• 174−260 MHzThe received signals from the antenna connector (J1) arepassed through two RX switches (RL3 and D56) and thetuned BPF (D51), then applied to the RF amplifier (Q34).The amplified signals are passed through the BPF (D45),attenuator (R139, 144, 147) and RX switch (D36) beforebeing applied to the 1st mixer (IC19).• 260−375 MHzThe received signals from the antenna connector (J1) arepassed through two RX switches (RL3 and D57) and thetuned BPF (D50), then applied to the RF amplifier (Q35).The amplified signals are passed through the BPF (D465),attenuator (R142, 143, 150) and RX switch (D37) beforebeing applied to the 1st mixer (IC19).• 375−550 MHzThe received signals from the antenna connector (J1) arepassed through the LPF (L101, 104, 108, C342, 346) andHPF (L77, 80, C296, 297, 303, 308), then applied to theRF amplifier (Q28) via TX/RX switch (D53, 61, 62). Theamplified signals are passed through the RX switch (RL1),attenuator (D28) and tuned BPF (D19, 21, 24, 27), beforebeing applied to another RF amplifier (Q20). The amplifiedsignals are applied to the 1st mixer (IC19) via the anothertuned BPF (D11, 13, 15, 17) and RX switch (D8).While the diversity operation is activated, the receivedsignals are also input from antenna connector ANT-2 (J2).The received signals are passed through the LPF (L103,106, 109, C344, 348), HPF (L95, 99, C329, 333, 338),antenna switch (D69, 73, 74) and limitter (D63, 66), thenapplied to the RF amplifier (Q29).The amplified signals are applied to the RX switch (RL1),and gone through the same process as the received signalsfrom ANT-1 (J1).RFAMPRXSWLPFHPFATTRXSWATTBPF ATTRXSWHPFRFAMP ATTRFAMPBPFATTRFAMPLPFANTSWBPFRFAMPBPFRFAMPRXSWLPFRFAMPBPFRFAMPLPFBPFATTRFAMPHPFBPFBPFRXSWBPFBPF RXSWBPFRFAMPRXSWRXSWRFAMPTX/RXSWRXSWHPFATTRXSWANTENNAATTRXSWRXSWRXSWANTSWBPFANTENNARFAMPD62TX/RXSWD59D77D75D61D53LIMITD10,D32D8D64,D67D11D58RL1D14,D76Q29D60Q28D38D16D70,D13,D65,D71,D72D23,Q38D28D19,D55,Q37D24,RL2Q30D17D63,D66D18,Q20D30Q32D48,D49D15,D12,LIMIT375−550 MHzD40,D78,LIMIT375−550 MHz D69,D73,D74D44D35D26118−174 MHzD7118−174 MHzLeft bandRight bandD41,D27D68Q39D43LIMITD20,D54,Q33810−1000 MHzD37D51Q18D50D46D45Q35D80D22D9Q40D36Q23Q34174−260 MHz260−375 MHzRL3D57D56D79Q19D21,• RF CIRCUITS
