CASTEL0061Paging Transmitter

8 T800-32-0010 Fitting Instructions 419-83210-00 419-83210-00 T800-32-0010 Fitting Instructions 1 Figure 8 Pinouts for D-Range 2 1 23 45 6 8 9 10 2004f_01 DATA DATA Lock detect Coaxial socket(externalreferencefrequency) 7 T800-32-0010 Paging BoardThe T800-32-0010 PCB can be fitted to Tait T800 Series II transmitters to ena-ble them to function as low-speed paging transmitters. This paging board isfor transmitters that will be connected to an external frequency standard. It isa DFSK Modulator, suitable for POCSAG or similar paging data formats. Ref-erence frequency stability is determined by the stability of the external stand-ard. The PCB is not designed for use with 66 to 88MHz equipment. Newer T800 transmittters have a Micromatch connector in the audio proces-sor compartment. This simplifies installation. This fitting instruction describes how to fit the PCB into existing T800 trans-mitters. You need to be proficient in the soldering of SMD components. Itmay be preferable to obtain a T800 transmitter already fitted with this boardfrom your Tait dealer or national sales office. Parts RequiredThe T800-32-0010 kit should contain the following items: 1 x T800-32-0010 DFSK modulator board1 x terminated coaxial cable1 x T800-03-1000 auxiliary D-range kit4 x M3 x 8 Taptite Pan Torx screws1 x coaxial socket1 x 47 ohm resistor SMD 08051 x terminated 8-way ribbon cable1 x terminated 4-way ribbon cable InstallationCaution: The radio must be powered off for this modification. After modi-fication, do not remove the coaxial lead from the socket unless theradio is powered off. 1. Remove the TCXO module from the synthesiser compartment of the T800 transmitter. 2. Fit the miniature coaxial socket (=SK710) and 47 Ohm SMD resistor (=R705) to the PCB pads provided beneath the TCXO, as shown in Fig-ure 1. 2 T800-32-0010 Fitting Instructions 419-83210-00 419-83210-00 T800-32-0010 Fitting Instructions 7 Figure 1 Location Of Socket And SMD Resistor Note: Keep the angle of the coaxial socket steep to ensure that there is space for theMicromatch cable as well as for the coaxial cable. 3. Remove the two screws and cover plate from the second D-range mounting hole at the rear of the T800 chassis. (If the transmitter already has a second D-range, this must be removed so that the D-range with a second Micromatch socket can be fitted.) 4. Remove R291, R289, and R296 from the audio processor (shown in Figure 2). Figure 2 T800 Transmitter Audio Processor (older version without Micromatch connector) - Top Side R291 S6 S7 S5 R289 R296 4. Using an AC-coupled oscilloscope set to 50 mV/div, observe the signal at TP2. Adjust RV2 until the triangle wave amplitude has been mini-mised. 5. Apply 600 Hz to the DATA line. Use a modulation analyser to observe the frequency deviation on the output of the transmitter. Adjust RV1 to get 4.5 kHz deviation on the modulation analyser. 6. Observe the transmitter ’s VCO control line using an AC-coupled oscil-loscope set to at least 20 mV/div and 0.5ms/div. Vary the input fre-quency down to low frequencies (for example 100 Hz) and check that the control line still has a good square wave. Note: You may have to re-adjust RV2 and RV1 alternately to achieve a square waveon the VCO control line and a 4.5 kHz deviation. Figure 7 shows a typical 100Hz VCO control line waveform with RV1 and RV2 set correctly. Figure 7 100 Hz VCO Control Line Waveform Note: If the lower cut off frequency of an AC coupled oscilloscope is too high,excessive distortion may be introduced which will result in 'sag' on the squarewave displayed. Determine if this is a problem by directly monitoring theoriginal square wave source and observe any sag.If there is sag, switch the oscilloscope to DC and use a 10μ F capacitor inseries with the scope probe (observing the correct polarity) to directly monitorthe VCO control line. Note that the trace settling time will be approximatelyone minute. 6 T800-32-0010 Fitting Instructions 419-83210-00 419-83210-00 T800-32-0010 Fitting Instructions 3 Figure 6 shows the location of these resistors on the PCB. Figure 6 Location of Zero Ohm Resistors For a different frequency, calculate the resistor pattern as follows:1. Divide the external oscillator frequency by 100 kHz. 2. Convert the result into binary. 3. Where there is a 0 in the binary number, place a zero ohm resistor in the equivalent position. Where there is a 1, leave an open link. Modulation AdjustmentBefore the paging transmitter can be used, its modulation must be set up cor-rectly.1. Apply +5 V DC to the DATA input (see Figure 8 for D-range 2 pin assignments) and observe the transmitter output using a frequencycounter. The output should read the carrier frequency. 2. Remove the +5 V DC from the DATA input and apply a ground ( 0 V) to the DATA input. Observe the transmitter output with a frequency counter. Adjust RV3 to get an output of F carrier + 4.5 kHz. 3. Remove the 0 V from the DATA line and apply a 100 Hz 5 Vp-p square wave. MSB LSB N7 N6 N5 N4 N3 N2 N1 N0 R92 R93 R94 R95 R96 R97 R98 R99 RV3 92 IC 14 TP2 99989796 93 94 95 5. Remove R718 and R719 from the synthesiser compartment (shown in Figure 3). Figure 3 T800 Transmitter Microntroller and Synthesiser Compartments 6. Remove R841 and R842 (SMD) from the microcontroller compartment (shown in Figure 3) to disconnect the appropriate lines from the micro-controller. 7. Lay the T800-32-0010 PCB above the exciter compartment with the component side up and positioned so that the Micromatch sockets are on the side closer to the front panel of the radio. 8. Connect the 8-way ribbon cable to the SK200 Micromatch socket in the audio compartment and connect the other end to the Micromatch socket SK3 on the PCB. R718 R719 R841 & R842 4 T800-32-0010 Fitting Instructions 419-83210-00 419-83210-00 T800-32-0010 Fitting Instructions 5 If there is no Micromatch socket in the audio compartment (olderSeries II transmitters), connect wires from the PCB to the audio com-partment as follows. F…

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G P A B C D E F G H J K L 54321 #R93 #R94 #R97 &IC14 &IC6 &R71 C1 C10 C11 C12 C13A C13B C13C C13D C14A C14B C2 C20 C21 C22 C23 C24 C25 C26 C27 C29 C3 C34 C35 C36 C37 C39 C4 C40 C45 C46 C47 C48 C49 C5 C50 C51 C52 C60 C61 C62 C63 C64 C65 C66 C67 C68 C69 C6A C6B C70 C71 C72 C73 C7A C7B C8 C9 D1 D2 D3 D4 D5 D6 D7 D8 IC1 IC10 IC11 IC12 IC13 IC2 IC3 IC4 IC5 IC7 IC8 IC9 L1 LINK1 LINK2 LINK3 Q1 Q2 Q3 R1 R10 R100 R11 R12 R13 R14 R15 R16 R17 R18 R19 R2 R20 R21 R22 R23 R24 R25 R26 R27 R28 R29 R3 R30 R31 R32 R33 R34 R35 R36 R37 R38 R39 R4 R40 R41 R42 R43 R44 R45 R46 R47 R48 R49 R5 R50 R51 R52 R53 R54 R55 R56 R57 R58 R59 R6 R60 R61 R62 R63 R64 R65 R66 R67 R68 R69 R70 R72 R73 R74 R75 R76 R77 R78 R79 R7A R7B R8 R80 R81 R82 R83 R84 R85 R86 R87 R88 R89 R9 R90 R91 R92 R95 R96R98R99 RV1 RV2 RV3 S1 S2 S3 S4 S5 S6 S7 SK1 SK2 SK3 SK4 TOP TP1 TP2 XTAL1 XTAL2 TAIT ELECTRONICS T800-32 PCB LAYOUT - TOP SIDE IPN:ISS:ID:DATE: 220-01512-03B1.TA29 Dec 1998 Scale:1.8:1 ; Rotation: 0 degrees

M850-00 T856/857 Installation F2.1 Copyright TEL 31/09/98 2 T856/857 Installation 2.1 Rack Mounting The T856 transmitter and T857 exciter are designed for use in a standard 483mm rackframe using a Tait T800 Series II guide. The guide is securely mounted to the rack framewith front and rear retaining screws, and the T856/857 is secured into the guide withtwo front panel mounting screws. Figure 2.1 shows a standard, double module guide which can also be fitted with an optional backplane PCB to locate and mate the rearD-range connector(s). For more information on available guide kits, refer to the T800Ancillary Equipment Service Manual or your nearest Tait Dealer or Customer ServiceOrganisation. A rear mounted N-type connector is used for RF output on the T856/857, while all DC,audio and control connections are via the rear mounted D-range connector, D-range 1(PL100). An additional rear D-range connector (T800-03-0000) can be fitted whenremote multichannel operation, or additional control or low frequency lines arerequired (refer to Figure 2.2 ). 2.2 Rack Wiring The D-range input and output connections are shown in Figure 2.3 and Figure 2.4 . Ensure that the cables are not subjected to any stresses due to tight bends or incorrectlengths.Make sure the RF coax cable to the N-type connector is free from sharp bends or twists.If access to the rear of the rack frame is restricted, the cable should be long enough toallow the chassis to be fully withdrawn from the guide. Figure 2.3 T856/857 D-Range 1 Wiring - Rear View Figure 2.4 T856/857 D-Range 2 Wiring - Rear View (standard T800-03-0000 kit) Note: Figure 2.4 above shows the standard pin allocations for the T800-03-0000 auxiliary D-range kit. A T800-03 auxiliary D-range kit is also available forspecial applications requiring custom internal wiring. Front PanelMounting Holes Rack Mounting Holes Rack Mounting Holes Rack Mounting Holes Slots For D-RangeConnectors Rack Mounting Holes Aperture For RFConnectors Optional Backplane PCBMounts On Rear Of Guide N-Type Connector D-Range Plug(D-Range 1) Space For OptionalD-Range Plug(D-Range 2) Front Panel Mounting Hole Figure 2.2 T856/857 Chassis Connectors Figure 2.1 T800-41-0002 Double Guide Kit

1 23 45 6 7 8 9 10 11 12 1314 15 External CTCSS input:1kHz deviation @150Hz (500mV rms) To key transmitter:high impedance<0.7V = key High isolationkeying option:6 to 50V DC To key PA, opencollector Can be configured asAudio 1 by internallink resistors if required Short together fornormal operation Sensitivity: -30dBm External/auxiliaryaudio processing Power supply, -ve earth 10.8 to 16V DC Line I/P1CTCSSSerial ComAudio 2Tx EnableLine I/P4Line I/P3Line I/P2 Opto Key + Opto Key - +13.8V Gnd Tx Key Can be configured as Audio 1 by internal link resistors if required.Refer to Part I. Open drain type;capable of sinking2.25mA via 2k2 Ω ; V max. = 5V ds 1 23 45 6 7 8 9 10 11 12 1314 15 CH_SLCT 0 CH_SLCT 1 CH_SLCT 2CH_SLCT 3CH_SLCT 4CH_SLCT 5CH_SLCT 6 CH_SLCT 7 GND TX RELAY DRV CTCSS DISABLE SERIAL COM AUX-OUT 0AUX-OUT 1AUX-OUT 2 F2.2 T856/857 Installation M850-00 29/02/00 Copyright TEL 2.3 Power Supply If a power supply other than an appropriate Tait model is used, ensure that it is capableof providing enough current to drive the T800 system and is also free from excessiveripple or noise.The system should be protected by the use of appropriately rated fuses in the powersupply.Note: It is particularly important when the prime power source is a battery thatfuses be employed in all supply lines. 2.4 Reverse Polarity & Overvoltage Protection A crowbar diode is fitted to all T856 transmitters and T857 exciters for protectionagainst connection to a power supply of incorrect polarity. It also provides overvoltageprotection from voltage transients caused by lightning strikes.Note: A fuse must be fitted in the power supply line for the diode to provide effec-tive protection.

C1.8T856/857 General InformationM850-00 29/02/00Copyright TEL 1.2Specifications 1.2.1Introduction The performance figures given are minimum figures, unless otherwise indicated, for equipment tuned with the maximum switching range and operating at standard room temperature (+22°C to +28°C) and standard test voltage (13.8V DC). Where applicable, the test methods used to obtain the following performance figures are those described in the EIA and ETS specifications. However, there are several parameters for which performance according to the CEPT specification is given. Refer toSection 1.2.6 for details of test standards. Details of test methods and the conditions which apply for Type Approval testing in all countries can be obtained from Tait Electronics Ltd. The terms "wide bandwidth", "mid bandwidth" and "narrow bandwidth" used in this and following sections are defined in the following table. 1.2.2General Number Of Channels.. 128 (standard) 1 Supply Voltage: Operating Voltage .. 10.8 to 16V DC Standard Test Voltage .. 13.8V DC Polarity .. negative earth only Polarity Protection .. crowbar diode Line Keying Supply (if required) .. -50V DC Supply Current: Transmit- T856.. 5.5A (typical) - T857.. 750mA Standby - T856.. 165mA (typical) - T857.. 150mA (typical) Operating Temperature Range .. -20°C to +60°C Channel Spacing Modulation 100% Deviation Receiver IF Bandwidth Wide Bandwidth25kHz±5.0kHz15.0kHz Mid Bandwidth20kHz±4.0kHz12.0kHz Narrow Bandwidth12.5kHz±2.5kHz7.5kHz 1. Additional channels may be factory programmed. Contact your nearest Tait Dealer or Customer Service Organisation. M850-00T856/857 General InformationC1.9 Copyright TEL29/02/00 Dimensions: Height .. 183mm Width .. 60mm Length .. 322mm Weight .. 2.1kg Time-Out Timer (optional) .. 0 to 5 minutes 1 adjustable in 10 sec- ond steps Tail Timer .. 0 to 5 seconds adjustable in 100ms 2 steps Transmit Key Time.. <30ms Transmit Lockout Timer.. 0 to 1 minute adjustable in 10 second steps 1.2.3RF Section Frequency Range .. 400-520MHz (refer to Section 1.4 and Section 1.5) Modulation Type .. FM Frequency Increment .. 5 or 6.25kHz Switching Range .. 8MHz (i.e. ±4MHz from the centre frequency) Load Impedance .. 50 ohms Frequency Stability.. ±1ppm, -20°C to +60°C (see also Section 1.4 and Section 1.5) Adjacent Channel Power (full deviation): Wide Bandwidth (WB).. -75dBc (±25kHz/15kHz B/W) Mid Bandwidth (MB).. -70dBc (±20kHz/12kHz B/W) Narrow Bandwidth (NB).. -65dBc (±12.5kHz/7.5kHz B/W) Transmitter Switching.. complies with ETS 300 113 1. Adjustable from 0 to 10 minutes in PGM800Win version 2.12 and later. 2. Adjustable in 20ms steps in PGM800Win version 2.12 and later. C1.10T856/857 General InformationM850-00 29/02/00Copyright TEL Transmitter Side Band Noise: (no modulation, 15kHz bandwidth) At ±25kHz .. -95dBc At ±1MHz .. -105dBc Intermodulation .. -40dBc with interfering signal of -30dBc .. -70dBc with 25dB isolation & interfering signal of -30dBc (PA with output isolator) T856 Mismatch Capability: Ruggedness .. refer to your nearest Tait Dealer or Customer Service Organisation Stability .. 3:1 VSWR (all phase angles) Radiated Spurious Emissions: Transmit .. -36dBm to 1GHz -30dBm 1GHz to 4GHz Standby .. -57dBm to 1GHz -47dBm 1GHz to 4GHz Conducted Spurious Emissions: (T856 Only) Transmit .. -36dBm to 1GHz -30dBm 1GHz to 4GHz Standby .. -57dBm to 1GHz -47dBm 1GHz to 4GHz Power Output: T856- Rated Power.. 25W (see Duty Cycle) - Range Of Adjustment.. 5-25W T857.. 1W ±300mW Duty Cycle (T856 Only).. 100% @ 25W at +25°C .. 25% @ 25W at +60°C .. 100% @ 10W at +40°C 1.2.4Audio Processor 1.2.4.1Inputs Inputs Available .. line, microphone and CTCSS Line Input: Impedance .. 600 ohms (balanced) Sensitivity (60% modulation @ 1kHz)- With Compressor .. -50dBm Without Compressor .. -30dBm M850-00T856/857 General InformationC1.11 Copyright TEL29/02/00 Microphone Input: Impedance .. 600 ohms Sensitivity (60% modulation @ 1kHz)- With Compressor .. -70dBm Without Compressor .. -50dBm 1.2.4.2Modulation Characteristics Frequency Response .. flat or pre-emphasised (optional) (below limiting) Line And Microphone Inputs: Pre-emphasised Response- Bandwidth .. 300Hz to 3kHz (WB & MB) .. 300Hz to 2.55kHz (NB) Below Limiting .. within +1, -3dB of a 6dB/octave pre-emphasis characteristic Flat Response .. within +1, -2dB of output at 1kHz Above Limiting Response .. within +1, -2dB of a flat response (ref. 1kHz) Distortion .. 2% max. Hum And Noise: Wide Bandwidth .. -55dB (300Hz to 3kHz [EIA]) typical Mid Bandwidth.. -54dB (CEPT) Narrow Bandwidth.. -50dB (CEPT) Compressor (optional): Attack Time .. 10ms Decay Time .. 800ms Range .. 50dB 1.2.4.3CTCSS Standard Tones.. all 37 EIA group A, B and C tones plus 13 commonly used tones Frequency Error.. 0.08% max. (from EIA tones) Generated Tone Distortion.. 1.2% max. Generated Tone Flatness.. flat across 67 to 250.3Hz to within 1dB Modulation Level.. adjustable Modulated Distortion.. <5% C1.12T856/857 General InformationM850-00 29/02/00Copyright TEL 1.2.5Microcontroller Auxiliary Ports: Open Drain Type.. capable of sinking 2.25mA via 2k2Ω V ds max... 5V 1.2.6Test Standards Where applicable, this equipment is tested in accordance with the following standards. 1.2.6.1European Telecommunication Standard ETS 300 086 January 1991 Radio equipment and systems; land mobile service; technical characteristics and test conditions for radio equipment with an internal or external RF connector intended pri- marily for analogue speech. ETS 300 113 March 1996 Radio equipment and systems; land mobile service; technical characteristics and test conditions for radio equipment intended for the transmission of data (and speech) and having an antenna connector. ETS 300 219 October 1993 Radio equipment and systems; land mobile service; technical characteristics and test conditions for radio equipment transmitting signals to initiate a specific response in the receiver. ETS 300 279 February 1996 Radio equipment and systems; electromagnetic compatibil…

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M850-00 T858/859 Installation F3.1 Copyright TEL 31/01/99 3 T858/859 Installation 3.1 Rack Mounting Caution: If you require continuous operation of the T858, leave the rack moduleposition immediately adjacent to the finned heatsink empty. Thereshould be adequate airflow over the fins at all times. Extra airflow canbe provided by fitting an auxiliary fan kit such as the T800-19-0010(refer to the T800 Ancillary Equipment Service Manual or your nearestTait Dealer or Customer Service Organisation for more details). The T858 and T859 PAs are designedfor use in a standard 483mm rack frameusing Tait T800 Series II guide rails.The guide rails are securely mounted tothe rack frame with front and rearretaining screws, and the PA is securedinto the guide with two (T858) or four(T859) front panel mounting screws.Figure 3.1 shows the standard, double width guide designed for use with theT859, while Figure 3.3 shows how the PA can be latched in the extended posi-tion. For more information on availa-ble guide kits, refer to the T800Ancillary Equipment Service Manualor your nearest Tait Dealer or CustomerService Organisation. Figure 3.1 T800-45-0001 PA Guide Kit The PA rear panel has three connectors: a BNC for RF input (from an adjacent T857exciter), an N-type for RF output and a D-range for all DC, audio and control connec-tions (refer to Figure 3.2 ). Figure 3.2 T858/859 Chassis Connectors Figure 3.3 T858/859 PA In Latched Position Note: You will need appropriate extension leads if you wish to carry out anyadjustment procedures with the PA withdrawn from the rack in the latchedposition. Alternatively, disconnect and withdraw the PA and reconnect itbehind the rack. 3.2 Rack Wiring The D-range input and output connections are shown in Figure 3.4 . Ensure that the cables are not subjected to any stresses due to tight bends or incorrect lengths.Make sure the RF coax cables to the N-type and BNC connectors are free from sharpbends or twists. If access to the rear of the rack frame is restricted, the cables should belong enough to allow the chassis to be fully withdrawn from the guide. Figure 3.4 T858/859 D-Range Wiring - Rear View Front PanelMounting Holes Rack MountingHoles Rack MountingHoles Rack Mounting Holes N-Type ConnectorBNC Connector D-Range Connector N-Type ConnectorBNC Connector D-Range Connector T858 T859 RF OutputRF InputD-range Top Rail Bottom Rail 1 23 45 6 7 8 9 10 11 12 1314 15 Normally low, floaton alarm conditions.500mA sink capability. Pull low to enablealarm outputs Power supply, -ve earth Will drive a coil meter 10.8 to 16V DC Reverse Power Metering Forward Power Metering Reverse Power AlarmForward Power Alarm Tx Key +13.8V Gnd F3.2 T858/859 Installation M850-00 29/02/00 Copyright TEL 3.3 Power Supply If a power supply other than an appropriate Tait model is used, ensure that it is capableof providing enough current to drive the T800 system and is also free from excessiveripple or noise.The system should be protected by the use of appropriately rated fuses in the powersupply.Note: It is particularly important when the prime power source is a battery thatfuses be employed in all supply lines. Caution: Connect the power supply directly to the PA, and not via connector blocks. This will avoid overheating of connector blocks that are not ofthe correct current rating. 3.4 Reverse Polarity & Overvoltage Protection A crowbar diode is fitted to all T858/859 PAs for protection against connection to apower supply of incorrect polarity. It also provides overvoltage protection from voltagetransients caused by lightning strikes.Note: A fuse must be fitted in the power supply line for the diode to provide effec-tive protection.

D1.14T858/859 General InformationM850-00 29/02/00Copyright TEL 1.3Specifications 1.3.1Introduction The performance figures given are minimum figures, unless otherwise indicated, for equipment operating at standard room temperature (+22°C to +28°C) and standard test voltage (13.8V DC). Ambient temperature is defined as the temperature of the air at the input to the cooling fan mounted on the heatsink, or immediately surrounding the heatsink if a fan is not fit- ted. Where applicable, the test methods used to obtain the following performance figures are those described in the ETS specification. Refer to Section 1.3.3 for details of test standards. Details of test methods and the conditions which apply for Type Approval testing in all countries can be obtained from Tait Electronics Ltd. 1.3.2General Power Output: T858- Rated Power.. 50W - Range Of Adjustment .. 10 to 60W (typical) T859- Rated Power.. 100W - Range Of Adjustment .. 20 to 110W (typical) Input Power.. 700 to 1300mW Duty Cycle Rating: T858.. 50W continuous to +60°C ambient temperature .. 60W continuous to +40°C ambient temperature T859.. 100W continuous to +60°C ambient temperature Intermodulation.. -70dBc or -40dBi 1 with 25dB isolation (PA with output isolator)& interfering signal of -30dBc Mismatch Capability: Ruggedness .. refer to your nearest Tait Dealer or Customer Service Organisation Stability .. 5:1 VSWR (all phase angles) 1. dBi denotes the level of intermodulation product relative to the interfering signal. M850-00T858/859 General InformationD1.15 Copyright TEL29/02/00 Supply Voltage: Operating Voltage .. 10.8 to 16V DC Standard Test Voltage .. 13.8V DC Polarity.. negative earth only Polarity Protection.. crowbar diode Maximum Supply Current (T858 @ 50W, T859 @ 100W): Standby .. 50mA Transmit - T858 without power module .. 11A - T858 with power module.. 12A (11A typical) - T859 without power module .. 22A - T859 with power module.. 23A (21A typical) Spurious Emissions: Conducted- Transmit .. -36dBm to 1GHz -30dBm 1GHz to 4GHz - Standby .. -57dBm to 1GHz -47dBm 1GHz to 4GHz Radiated- Transmit .. -36dBm to 1GHz -30dBm 1GHz to 4GHz - Standby .. -57dBm to 1GHz -47dBm 1GHz to 4GHz Operating Temperature Range.. -30°C to +60°C ambient temperature Dimensions: Height.. 183mm Width- T858.. 60mm - T859.. 120mm Length.. 340mm Weight: T858.. 3.1kg T859.. 3.5kg 1.3.3Test Standards Where applicable, this equipment is tested in accordance with the following standards. 1.3.3.1European Telecommunication Standard ETS 300 086 January 1991 Radio equipment and systems; land mobile service; technical characteristics and test conditions for radio equipment with an internal or external RF connector intended pri- marily for analogue speech. D1.16T858/859 General InformationM850-00 29/02/00Copyright TEL ETS 300 113 March 1996 Radio equipment and systems; land mobile service; technical characteristics and test conditions for radio equipment intended for the transmission of data (and speech) and having an antenna connector. ETS 300 219 October 1993 Radio equipment and systems; land mobile service; technical characteristics and test conditions for radio equipment transmitting signals to initiate a specific response in the receiver. ETS 300 279 February 1996 Radio equipment and systems; electromagnetic compatibility (EMC) standard for pri- vate land mobile radio (PMR) and ancillary equipment (speech and/or non-speech). 1.3.3.2DTI CEPT Recommendation T/R-24-01 Annex I: 1988 Technical characteristics and test conditions for radio equipment in the land mobile service intended primarily for analogue speech. Annex II: 1988 Technical characteristics of radio equipment in the land mobile service with regard to quality and stability of transmission. 1.3.3.3Telecommunications Industry Association ANSI/TIA/EIA-603-1992 Land mobile FM or PM communications equipment measurement and performance standards.

M850-00T856/857 Circuit OperationC2.3 Copyright TEL31/09/98 2.1Introduction The individual circuit blocks which make up the T856 and T857 are: • synthesiser •VCO • audio processor • drive amplifier • power amplifier (T856 only) • voltage regulators. Each of these circuit blocks is set in its own shielded compartment, formed as an inte- gral part of the main chassis. The configuration of the circuit blocks may be seen on a functional level in Figure 2.1 and Figure 2.2. Refer to the circuit diagrams in Section 6.2 (T856) or 6.3 (T857) for more detail. Figure 2.1 T856 High Level Block Diagram Figure 2.2 T857 High Level Block Diagram Ramp Gen. Time Delay Time Delay Time Delay Audio Processor Synthesiser +22dBm Reference Oscillator 12.8MHz Microphone Line Transformer Lock Detect PIN Switch Power Control Drive Amp. PA VCO Gate Directional Coupler Low Pass Filter Exciter Output (+30dBm to +33dBm) Transmitter Output (25W) Tx Reg & Audio Processor Synthesiser +22dBm Reference Oscillator 12.8MHz Microphone Line Transformer Lock Detect PIN Switch Switching Control Drive Amp. Gate Exciter Output (+28dBm to +31dBm) & Ramp Gen. Tx Reg VCO Time Delay Time Delay Low Pass Filter PA Control Signal (via exciter RF coax) C2.4T856/857 Circuit OperationM850-00 29/02/00Copyright TEL 2.2Microcontroller (Refer to the microcontroller circuit diagram (sheet 8) in Section 6.2 or 6.3.) Figure 2.3 T856/857 Microcontroller Block Diagram Overall system control of the T856/857 is accomplished by the use of a member of the 80C51 family of microcontrollers (IC810). It runs from internal ROM and RAM, thus leaving all four ports free for input/output functions. Non-volatile data storage is achieved by serial communication with a 16kBit EEPROM (IC820). This serial bus is also used by the microcontroller to program the synthesiser (IC740) and deviation control EPOTS (IC220). The main tasks of the microcontroller are as follows: • program the synthesiser and EPOT; • interface with the PGM800Win programming software at 9600 baud via the serial communication lines on D-range 1 (PL100) & D-range 2; • monitor channel change inputs from D-range 2; • generate timing waveforms for CTCSS encoding; • coordinate and implement timing control of the exciter/transmitter. • control the front panel "Supply" LED (refer to Section 5.3). 5VReset 5V Digital Regulator Watchdog Reset Channel Select Port Auxiliary Output Port Microcontroller 12.8MHz Clock Microcontroller Cavity CTCSS Tone External Serial Port EEPROM Synthesiser Dual Digital Potentiometer CTCSS Encoder Converter M850-00T856/857 Circuit OperationC2.5 Copyright TEL31/09/98 2.3Synthesised Local Oscillator (Refer to the synthesiser circuit diagram (sheet 7) in Section 6.2 or 6.3 and the VCO cir- cuit diagram in Part E.) Figure 2.4 T856/857 Synthesiser Block Diagram The synthesiser (IC740) employs a phase-locked loop (PLL) to lock a voltage controlled oscillator (VCO) to a given reference frequency. The synthesiser receives the divider information from the control microprocessor via a 3 wire serial bus (clock, data, enable). When the data has been latched in, the synthesiser processes the incoming signals from the VCO buffer (f in ) and the phase modulator (f ref ). A reference oscillator at 12.8MHz (=IC700) is buffered (IC710 pins 3 & 4) and divided down to 200kHz (IC730). This 200kHz square wave is then summed with the modulat- ing audio and passed to an integrator (IC720 pins 9 & 8, Q710, Q720). This produces a ramping waveform which is centred around a DC level determined by the incoming audio. IC720 pins 5 & 6 perform as a comparator, ultimately producing a phase-modu- lated 200kHz square wave. This is followed by another phase shifting stage (IC720 pins 3 & 4, Q730, Q740), before being divided down to 6.25kHz or 5kHz within the synthe- siser IC (IC740). A buffered output of the VCO (Q795) is divided with a prescaler and programmable divider which is incorporated into the synthesiser chip (IC740). This signal is compared with the phase modulated reference signal at the phase detector (also part of the synthe- siser chip). The phase detector outputs drive a balanced charge pump circuit (Q760, Q770, Q775, Q780, Q785) and active loop filter (IC750 pins 5, 6 & 7, Q790) which pro- duces a DC voltage between 0V and 20V to tune the VCO. This VCO control line is fur- ther filtered to attenuate noise and other spurious signals. Note that the VCO frequency increases with increasing control voltage. If the synthesiser loop loses lock, a pulsed signal appears at LD (pin 2) of IC740. This signal is filtered and buffered by IC750 pins 1, 2 & 3, producing the Lock-Detect signal used to shut off the power supply to the drive amplifier. IC750 pin 1 is at 20V when the synthesiser is out of lock. /R Reference Divider 12.8MHz Reference Oscillator Fixed Divider /64 Phase Modulator Ref Mod Phase Detector Charge Pump Loop Filter FREQUENCY SYNTHESISER IC Serial Bus Clk Data En Controller /N Programmable Divider 64/65 Prescaler VCO PCB VCO Modulation VCOBuffer Output Buffer +22dBm L.O. Divider Buffer f ref f in Σ C2.6T856/857 Circuit OperationM850-00 29/02/00Copyright TEL 2.3.1Two Point Modulation Frequency modulation occurs by modulating both the VCO input and the synthesiser reference input. This process is called two point modulation and ensures a flat modula- tion response from 67Hz to 3kHz (2.55kHz for narrow bandwidth). The PLL has a fast response time, allowing a Tx key-up time of <30ms. Because of this fast response time the PLL sees lowe…

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