Motorola Mtx Series Detailed Rev 6881088c46 E Manual
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FMR-2045A-2December 26, 2003 UHF Theory of Operation: Synthesizer11 The Frequency Generation Circuitry is composed of two main ICs: Fractional-N synthesizer (U201) VCO/Buffer IC (U241) Designed in conjunction to maximize compatibility, the two ICs provide many of the functions that normally would require additional circuitry. The synthesizer block diagram illustrates the interconnect and support circuitry used in the region. Refer to the relevant schematics for the reference designators. The...
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December 26, 2003FMR-2045A-2 12UHF Theory of Operation: Voltage-Controlled Oscillator (VCO) The loop filter which consist of C231, C232, C233, R231, R232 and R233 provides the necessary dc steering voltage for the VCO and determines the amount of noise and spur passing through. In achieving fast locking for the synthesizer, an internal adapt charge pump provides higher current at pin 45 of U201 to put synthesizer within the lock range. The required frequency is then locked by normal mode charge pump...
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FMR-2045A-2December 26, 2003 UHF Theory of Operation: Voltage-Controlled Oscillator (VCO) 13 The VCOBIC (U241) in conjunction with the Fractional-N synthesizer (U201) generates RF in both the receive and the transmit modes of operation. The TRB line (U241 pin 19) determines which oscillator and buffer will be enabled. A sample of the RF signal from the enabled oscillator is routed from U241 pin 12, through a low pass filter, to the prescaler input (U201 pin 32). After frequency comparison in the...
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December 26, 2003FMR-2045A-2 This page intentionally left blank. 14UHF Theory of Operation: Voltage-Controlled Oscillator (VCO)
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Chapter 2 UHF Circuit Board Layouts, Schematic Diagrams and Parts List 2.1 Notes for All Schematics and Circuit Boards * Component is frequency sensitive. Refer to the Electrical Parts List for value and usage. 1.Unless otherwise stated, resistances are in Ohms (k = 1000), and capacitances are in picofarads (pF) or microfarads (µF). 2.DC voltages are measured from point indicated to chassis ground using a Motorola DC multimeter or equivalent. Transmitter measurements should be made with a 1.2 µH choke...
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December 26, 2003FMR-2045A-2 This page intentionally left blank. 16UHF Circuit Board Layouts, Schematic Diagrams and Parts List: Notes for All Schematics and Circuit Boards
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Circuit Board/Schematic Diagrams and Parts List 17 FMR-2045A-2 December 26, 2003 2.2 Circuit Board/Schematic Diagrams and Parts List Figure 2-1. UHF (403-470MHz) Main Board Top Side PCB No. 8486458Z02 C505 R507 C502 VR5011 23 5PB501 43 2 FL304C521 FL302 VR440 C349 R3652 Y301 4 3 2 FL303 C352 R321 R324R345 R355 R360 C362 R342458 U302C324 C325C338 2 3 4 56 FL301 L311 L330 SH323 C320 C322 C381 L309 L310 R308R309 R310SH303 6 4 3 T30164 3 T302C319 C375R348 TP202TP302 1 23 5PB504 C511C512 C513 C514 C520 43...
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18Circuit Board/Schematic Diagrams and Parts ListDecember 26, 2003FMR-2045A-2 Figure 2-2. UHF (403-470MHz) Main Board Bottom Side PCB No. 8486458Z02 C449 C463 C524 C525 E401E402E403 E404E405 E406 26 1 7651 U409 C453 C456R411 R432 L410 L411 C458 C459 C466C526 C527 C528 C529 E400 R409 R457C431C433C436 C437 3 FL401 R414R415R420R426R463 C434C435 CR411 Q416 R419 R460 R461R462 SH402 U410 C328 C337 C359C523 R374 R3751 4 5 8 U303VR442 C277C278 C279C522 L505 U248 VR441 VR506 C358 C383 C390R373 R376 R377 R378...
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Circuit Board/Schematic Diagrams and Parts List19FMR-2045A-2December 26, 2003 Figure 2-3. UHF Controls And Switches Schematic Diagram B504 if B503 LI_ION VR5016.8V0.47uF C502 C505 100pFSWITCH S502 4 1 LOW5 HIGH36 TAB1 7 TAB2 2 R507 0 MECH_SWB+ Vdda VOL P100M100M101 VR441 6.8V 6.8V VR442PB503 SWITCH 1 2 .01uFC522 VR444 6.8V1 2SWITCHPB501 2PB502 SWITCH 1 6.8V VR440 .01uFC521 2SWITCHPB504 1 .01uFC523 EMER PTT SB2 SB3SB1 PB505 1 2SWITCH C520 .01uF6.8V VR443 Vdda 4 3 2 R506 47K 5 1 6IMX1 Q50510K R505 R502...
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20Circuit Board/Schematic Diagrams and Parts ListDecember 26, 2003FMR-2045A-2 Figure 2-4. UHF Receiver Front-End Schematic Diagram CR303 23 1 100K R302 7.5K R340 CR3022.0K R303 100pF C308 100pFC307 C305 13.9nH L30220pF 9.1pF C304 22nH L303C309 100pF 1 Q301 R328 0 3 2 G 3.9pFC303 3.6pFC301100K R301 C302 10pFCR301 L301 13.9nH RX_IN RXFE Bottom Shield RXFE Top Shield RX Mixer Diod Shield SH302 SHIELD 1 1 SHIELDSH304 SH301 SHIELD 1 Mixer Shield 1 SHIELDSH303 G 100pF C321 12K R304C314 0.1uFC315 100pF 180nH...