Motorola Gp328 Gp338 Detailed 6804110j64 F Manual
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Receiver6D-74.3 Automatic Gain Control Circuit(Refer to330-400MHz Receiver Front End Schematic Diagramon page 6D-16) The front end automatic gain control circuit is to provide automatic gain reduction of the front end RF amplifier via feedback. This action is necessary to prevent overloading of backend circuits. This is achieved by drawing some of the output power from the RF amplifier’s output. At high radio frequencies, capacitor C331 provides the low impedance path to ground for this purpose. CR308 is...
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6D-8Frequency Generation Circuitry5.0 Frequency Generation CircuitryThe Frequency Generation Circuitry is composed of two main ICs, the Fractional-N synthesizer (U201), and the 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....
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Frequency Generation Circuitry6D-95.1 Synthesizer(Refer to330-400MHz Synthesizer Schematic Diagramon page 6D-18) The Fractional-N Synthesizer uses a 16.8MHz crystal (FL201) to provide a reference for the system. The LVFractN IC (U201) further divides this to 2.1MHz, 2.225MHz, and 2.4MHz as reference frequencies. Together with C206, C207, C208, R204 and CR203 , they build up the reference oscillator which is capable of 2.5ppm stability over temperatures of -30 to 85°C. It also provides 16.8MHz at pin 19...
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6D-10Frequency Generation Circuitry5.2 VCO - Voltage Controlled Oscillator(Refer to330-400MHz Voltage Controlled Oscillator Schematic Diagramon page 6D-19) Figure 6-5VCO Block Diagram 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...
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Frequency Generation Circuitry6D-11The VCOBIC(U241) is operated at 4.54 V (VSF) and Fractional-N synthesizer (U201) at 3.3V. This difference in operating voltage requires a level shifter consisting of Q260 and Q261 on the TRB line. The operation logic is shown in Table 6-1. In the receive mode, U241 pin 19 is low or grounded. This activates the receive VCO by enabling the receive oscillator and the receive buffer of U241. The RF signal at U241 pin 8 is run through a matching network. The resulting RF...
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6D-12 Notes For All Schematics and Circuit Boards6.0 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 multime- ter or equivalent. Transmitter measurements should be made with a 1.2 µH choke in series with the...
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Circuit Board/Schematic Diagrams and Parts List6D-137.0 Circuit Board/Schematic Diagrams and Parts List E409E407R410 R418 R437 32 17 U406 1 16 1 7 22 821 U405 J4001 40C426 C425E408 C423 TP401 TP402 TP410R435 C443C444RT400 C427 C428 8 54 1 U407L401 VR447 C429 C424 R428 R429 R492SH400R478 R408 21 1 J403 20 22 VR450 TP405 R421 L400 VR434 TP406TP415D403R450Q417 3 4 R477 C441 C490 C491 C492C493 C494 C495 C496C497C471 C473 C472VR449 Q403 Q400 Q405 3 4 R401 R402 R403R405 R407 R416 R446 R448 R476R481R406 R447...
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6D-14Circuit Board/Schematic Diagrams and Parts List 2 S502 35 44 C 8 C S501 2 1 J101 4 3 2 J102 Q 111 3 4R101 R170M100 CR103 P100C108 R172 R133 H101 CR105 C172 C132 C173 R102 R131 R130 R132R109 L112 25 9 17 U102 1C133 C105 C130 C138C151 C170 C174 C134 C128 C135 C150 C152C126Q301 R304R340 R305R328 R306 R307 R303 R347 SH302 L340 L304 L306 L307 L303 L305 CR304 CR305CR303 C309 C315 C321 C395C307C310 C314 C380 C312 C318 C316 C313C317 C306 C311 R344R350 R343 M301 SH322 L331 L314 13 25 37 1U301 C337 C383 C390...
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Circuit Board/Schematic Diagrams and Parts List6D-15 DEMOD LVZIF_SEL RSSI 16.8MHzCLK DACRx DATA Vdda Vdda RX_IN RX_INJR5 RECEIVER DATA CLK DACRX DEMOD RSSI LVZIF_SEL 16.8MHz RX_INJSWB+ TX_INJ Vdda FGU 16.8MHz 4V_3.3V 5V CLK CSX DATA LOCK MODIN R5 CSX 4V_3.3VSWB+ LOCK MODIN 5V DATA RESET RX_IN TX_INJ UNSWB+ TRANSMITTER 5V CLK CSX 5V UNSWB+ RESETB503 B504 LI_ION C505 100pFR507 0 C502 0.47uF VR5016.8V1 5 HIGH32SWITCH S502 4 LOW Vdda VOLMECH_SWB+ 100pFC503VR506 6.8V 10V VR439L505 390nH 24V 2 1F501 2CR501...
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6D-16Circuit Board/Schematic Diagrams and Parts List L340 390nHHSMP3820 1 23 CR308 R317 1K 100pF C395C331 100pF 1K R347 R5 C311100K R307 R306 100K CR304 C306 CR305 C312 8.2pF 22nHL305 C313 12pFL306 19.71nH 19.71nHL307 5.1 pFC316 NUNU R305 470 R304 12K C321 100pF C309 100pF R303 1 K Q301 13 2 C307 0.1uF0.1uF C314 180nHL304C315 100pF C310 0.1uF R328 2.7 L303 33nHR340 8.2K 19.71nH L302C308 100pF 100K R301 12pF C302C305 12pF CR301 CR302 5.1pFC303 11pF C304 R302 L301100K 19.71nH1 CR303 23 C301 8.2pF RX_IN 1...