Wood and Douglas ST500 Technical Manual Download

Page: 6 / 18

1891 1210

1.0/November 1998

1.1 GENERAL DESCRIPTION

The ST500 can be configured for analogue or digital operation and is available in the
frequency range of 405 - 470MHz with a 12.5kHz channel spacing.

The transmitter requires a nominal 12 volt DC supply connected via PL7. However
the unit will function correctly within the limits of +6.0V to +14.0V. The output power
of the transmitter is normally preset to 100mW nominal.

The ST500 is intended to fit into OEM equipment housing by means of the three
connectors which protrude through the base of the unit.

Summary of Contents for ST500

Page 1: ...0 TRANSMITTER TECHNICAL MANUAL 1891 1210 Copyright Wood Douglas Ltd 1998 version 1 0 issue November 1998 LATTICE HOUSE BAUGHURST ROAD TADLEY HAMPSHIRE UK RG26 5LP Tel 44 0 118 981 1444 Fax 44 0 118 981 1567 ...

Page 2: ......

Page 3: ...FREQUENCY STAGE 10 3 5 FREQUENCY PROGRAMMING 14 Section 4 Technical specifications 19 DRAWINGS WS1494 XX7 GENERAL ARRANGEMENT FOR ST500 WD1632 001 CIRCUIT DIAGRAM FOR ST500 WD1632 XX2 COMPONENT OVERLAY FOR ST500 Sheet 1 of 3 WD1632 XX2 COMPONENT OVERLAY FOR ST500 Sheet 2 of 3 WD1632 XX2 COMPONENT OVERLAY FOR ST500 Sheet 3 of 3 C WD632 00 ITEM LIST FOR LEADED COMPONENTS FOR ST500 A SM1632 00 ITEM L...

Page 4: ...1891 1210 1 0 November 1998 ...

Page 5: ...ser make additional copies of the manual or store the information given on any electronic retrieval or mass storage system The company reserves the right to amend or change specifications of its products without prior notice in accordance with the company policy of continued product improvement NOTE This device complies with Part 15 of the FCC Rules Operation is subject to the condition that this ...

Page 6: ...a 12 5kHz channel spacing The transmitter requires a nominal 12 volt DC supply connected via PL7 However the unit will function correctly within the limits of 6 0V to 14 0V The output power of the transmitter is normally preset to 100mW nominal The ST500 is intended to fit into OEM equipment housing by means of the three connectors which protrude through the base of the unit ...

Page 7: ...ION REMARKS 1 0V 0 volts common ground 2 b T b Xb E transmit enable o c transmitter disabled LOW 0 8V transmitter enabled 1KÙ nom internal pull up to Vin 3 DIGITAL I P data input 0 3V to 0 12V DC coupled 4 ANALOGUE I P data input 300mV to 5V p p AC coupled 5 5V O P 5V supply output 50mA max current drain 6 RS232 I P serial programming input If not used leave un connected or ground refer to section...

Page 8: ...UNCTION REMARKS 1 0V 0 volts common ground 2 RF O P RF output 50 ohms output 3 0V 0 volts common ground Connector PL2 pin detail PIN NAME FUNCTION REMARKS 1 VIN positive supply 6 0V to 14 0V 2 0V 0 volts common ground Connector PL3 pin detail ...

Page 9: ...1 in the feedback network around IC1a RV1 acts as an analogue gain control When the transmitter is to be used with a digital modulation input then this input is fed from PL1 pin 3 via R1 to RV1 in the feedback network around IC1a RV1 is set mid way in this application such that it has no effect IC1a then functions as a comparator and produces an output which swings between approximately 0 7V and 4...

Page 10: ...ich is fed to the diodes via L9 Trimmer C32 provides coarse tuning of the oscillator frequency Varicap diode D2 is also loosely coupled into the oscillator circuit via C26 and provides a means of frequency modulating the oscillator The output from the oscillator is developed across R42 at the collector of TR5 and is fed via C40 to buffer amplifier IC5 This amplifier provides an increased output le...

Page 11: ...al output of the transmitter this is in order to minimise the effect of transmitter load changes on the oscillator frequency IC7 receives its DC power via microprocessor IC3 this allows IC7 to act as a switch in effect so that there is negligible RF output from the transmitter in the event that an out of lock condition is detected The output from IC7 is fed via C46 to the base of TR3 which functio...

Page 12: ...g input of IC4a is connected to the emitter of TR4 while the output of IC4a is fed via D5 and R36 to the base of TR4 This has the effect of forcing the emitter voltage of TR4 to track the voltage ramp at the wiper of RV4 The current in TR4 is thus ramped up at the beginning of a transmission and ramped down at the end and consequently the RF output power from the transmitter is similarly ramped up...

Page 13: ...L1 pin 10 of the transmitter must be connected to pin 2 of the PC serial port via a buffer circuit A 1k pull up resistor to 5V must also be provided as shown 3 5 2 Running the Software 1 Connect ST500 to a suitable supply and to the PC using the programming adaptor 2 Insert the ST500PRG disk into drive A and type A ST500PRG return then type 3 The user is then prompted to enter the serial port numb...

Page 14: ... table 458 7 MHZ Max Freq 458 95 MHz Sequential frequencies Chan 16 to 127 Table step 1 x 12 5 KHz Figure 3 NOTES 1 The synthesizer step frequency the reference TXCO frequency and the intermediate frequency are non programmable 2 Functions F9 F10 and F11 are not enabled 3 Function F5 is only enabled when a read back programming adaptor is used refer to Figure 2 This function displays the current f...

Page 15: ...erating channel as shown in the following table CHANNEL SELECTION PIN 8 PIN 9 PIN 10 CHANNEL LOW LOW LOW 7 LOW LOW HIGH 6 LOW HIGH LOW 5 LOW HIGH HIGH 4 HIGH LOW LOW 3 HIGH LOW HIGH 2 HIGH HIGH LOW 1 HIGH HIGH HIGH 0 The logic levels are LOW 0 8V HIGH 2V or floating 3 5 5 Programming Random Channels Random channels between 0 and 15 can be entered using the Up 8 and Down 9 arrow keys and then enter...

Page 16: ...utomatically When the frequency table has been generated the user then selects F6 to program the unit The function key F2 can be used to copy the contents of channel 16 31 to channel 0 15 to ease sequential programming 3 5 7 Programming from Customer Equipment In the event of a customer wishing to program the ST500 receiver from his own equipment then the following data sequence must be used allow...

Page 17: ...17 1 0 November 1998 1891 1210 ...

Page 18: ...led digital 3 to 12V square wave DC coupled Frequency response 9Hz to 3kHz at 3dB Deviation 1 5kHz nom 2 5kHz max Channel switching delay 50mS across switching bandwidth Channel spacing 12 5kHz Modulation type F1D F2D F3D Spurious emissions conducted radiated in accordance with ETS CEPT specifications Supply voltage 6 15V DC ve earth Supply current at 7 2V 100mA for 100mW output Interface connecti...

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