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BSR 113
Technical Manual
63 pgs1.82 Mb0

Multitone BSR 113 Technical Manual

BSR 113
TM1194A Issue B Page (i)
TECHNICAL MANUAL
for
UHF BASE STATION RECEIVER
MODEL BSR 113
(448MHz)
BSR 113
TM1194A Issue BPage (ii)
COMPANY LIABILITY
The information in this manual has been carefully compiled and checked for technical accuracy. Multitone Electronics plc accept no l iability for inaccuracies or errors. In line with the company policy of technical advancement, the information within this document may be changed. The user should ensure that the correct issue of the document is used. Comments or correspondence regarding this manual should be addressed to:
Multitone Electronics plc Technical Publications Kimbell Road Basingstoke Hampshire RG22 4AD England
ISSUE DATE
B February 1998
© Multitone Electronics plc 1996, 1998
BSR 113
TM1194A Issue B Page (iii)
CONTENTS
Page (I
)
Title Page
Page (ii
)
Company Liabilit
y
Page (iii
)
Contents
Page (iv
)
Effective Page List
Page (v
)
Safety Summar
y
Warnin
g
Page (vi
)
Cautions
Section 1 Introduction and Specification Section 2 Operating Instructions Section 3 Technical Description Section 4 Installation and Commissionin
g
Section 5 Servicin
g
Section 6 Spare Parts List Section 7 Diagrams
BSR 113
TM1194A Issue BPage (iv)
EFFECTIVE PAGE LIST
Page No. Issue Page No. Issue Page No. Issue
(I)
B3-7B5-7B
(ii)
B3-8B5-8B
(
iii
)
B3-9B5-9B
(iv)
B 3-10 B 5-10 B
(v)
B4-1B5-11B
(vi)
B4-2B5-12B
1-1 B 4-3 B 5-13 B 1-2 B 4-4 B 5-14 B
1-3 B 4-5 B 6-1 B 1-4 B 4-6 B 6-2 B
1-5 B 4-7 B 6-3 B 1-6 B 4-8 B 6-4 B
2-1 B 4-9 B 6-5 B 2-2 B 4-10 B 6-6 B
3-1 B 5-1 B 7-1 B 3-2 B 5-2 B 7-2 B
3-3 B 5-3 B 7-3/4 B 3-4 B 5-4 B 7-5/6 B
3-5 B 5-5 B 7-7/8 B 3-6 B 5-6 B 7-9/10 B
7-11 B
BSR 113
TM1194A Issue B Page (v)
MANY RESINS AND OTHER CHEMICALS USED IN THE MANUFACTURE OF ELECTRICAL COMPONENTS FITTED TO THIS BOARD GIVE OFF TOXIC FUMES WHEN INCINERATED. APPROPRIATE PRECAUTIONS SHOULD T HEREFORE BE TAKEN WHEN DISPOSING OF THESE ITEMS.
SAFETY SUMMARY
The following information applies to both operating and servicing personnel. General Warnings and Cautions will be found throughout the manual where they apply.
WARNING statements identify conditions or practices that could result in personal injur
y
or loss of life. CAUTION statements identify conditions or practices that could result in equipment
damage.
WARNING
BSR 113
TM1194A Issue BPage (vi)
CAUTIONS
DO NOT INSTALL THE RECEIVER WHERE IT MAY BE EXPOSED TO LIQUIDS, STRONG MAGNETIC FIELDS, EXTREME TEMPERATURES OR STRONG SUNLIGHT.
STATIC SENSITIVE DEVICES ARE USED W ITHIN THIS EQUIPMENT. CARE MUST BE TAKEN TO ENSURE DAMAGE TO THESE DEVICES IS NOT CAUSED BY HIGH LEVELS OF STAT IC ELECTRICITY. SPARE BOARDS OR CO MPONENTS SHOUL D BE STORED IN ANTI- STATIC PACKAGING W HEN NOT I NSTAL LED I N THE EQUI PMENT.
DIRECT CONNECTION OF THE BSR 113 TO PUBLIC TELEPHONE OPE RATOR (PTO
)
LINES IS PROHIBITED UNLESS NAT IONAL LINE CONNECTION APPROVAL HAS BEEN GRANTED BY THE APPROPRIATE REGULATORY AUTHORITY.
UNDER NO CIRCUMSTANCES SHOULD SK1 BE CONNECTED TO THE SYSTEM BUS OF MULTITONE ACCESS 1000 OR ACCESS 3000 SYSTEMS.
BSR 113
TM1194A Issue B Page 1 - 1
SECTION 1
INTRODUCTION AND SPECIFICATION
CONTENTS:
1. INTRODUCTION
2. FEATURES
3. PHYSICAL CONSTRUCTION SPECIFICATIONS
4. Performance Characteristics
5. Power Supply
6. Connectors
7. Physical Characteristics
8. Operational Environment
FIGURE Page
1. Simplified BSR Configuration 1-2
_______________________
INTRODUCTION
1. The Base Station Receiver model BSR 113 is an UHF double superheterodyne frequency modulated receiver, operating on a specified frequency within the range 448MHz to 449MHz. The BSR 113 is suitable for systems providing two-way speech between a base control unit and mobile transceivers, and for systems incorporating talkthrough between the mobile transcei vers via the base control unit. A simplified block diagram of a typical BSR 113 configuration is shown in Figure 1.
TRANSCEIVER
RECEIVER
STATION
BASE
TRANSMITTER
CONTROL
SYSTEM
TAG10500-2
(e.g. ACCESS 3000)
BSR 113
TM1194A Issue BPage 1 - 2
Figure 1: Simplified BSR Configuration
FEATURES
2. The BSR 113 has the following features:
Signal detect relay
6006 audio line and tone drivers
Speaker with volume control
Ability to link with other receivers
PHYSICAL CONSTRUCTION
3. The BSR 113 consists of a single Pri nted Cir cuit Board (PCB) mounted in a tough, moulded plastic outer casing, consisting of a base and a cover. The PCB is mounted on the base and a loudspeaker is fitted to the cover. Connector sockets are fitted to a cover plate at the rear of the unit. The speaker volume control is also located at the rear of the unit. The BSR 113 can be wall or shelf mounted.
BSR 113
TM1194A Issue B Page 1 - 3
SPECIFICATIONS
Performance Characteristics
4. The performance characteristics of the BSR 113 are as follows:
a) Frequency Range: 448.0 - 449.0MHz b) Suggested Frequencies: 1: 448.1250MHz
2: 448.1500MHz 3: 448.2250MHz 4: 448.3500MHz
5: 448.6750MHz c) Channel Spacing: 25kHz d) Intermediate Frequencies: 1st: 45MHz
2nd: 455kHz e) Crystal Frequency (1st LO): ƒx = ƒc - 45MHz
6
f) Sub-Audio Tone Frequencies: 88.5Hz, 103.5Hz, 114.8Hz, 127.3Hz,
141.3Hz g) Sub-Audio Tone Squelch: To EIA standard RS-220 h) Full System Deviation: ±5kHz for 20/25kHz channel spacing j) Sensitivity (conducted): <1µV for 12dB SINAD at 60% of full
system deviation k) Tone Squelch Sensitivity: <0.7µV at 15% of full system deviation l) Adjacent Channel Rejection: >70dB Standard (2 signal method) m) Spurious Response Rejection: >70dB (2 signal method) n) Intermodulation Response
Rejection: >60dB (3 signal method)
p) Audio Output (Internal
Loudspeaker): 100mW into 8
6
BSR 113
TM1194A Issue BPage 1 - 4
q) Audio Output External Line Level: -13dBm nominal (-4dBm max) to 600
6
(internal, pre-set) r) Radiated Power to Antenna: <2nW s) Cabinet Radiation: <2nW t) Signal Detect Relay Contact Rating: 100V DC, 250mA, non-inductive
Power Supply
5. The power supply requirements of the BSR 113 are as follows: a) Power Supply: 12V DC b) Current Consumption: <400mA maximum
Connectors
6. The BSR 113 is fitted with the following connectors: a) SK2: Audio/Tone Out b) SK1: Squelch Relay c) SK3: DC Power Supply d) SK7: Antenna
Physical Characteristics
7. The physical characteristics of the BSR 113 are as follows: a) Overall Dimensions: Width: 235mm
Depth: 207mm Height: 50mm
b) Weight: 0.7kg
BSR 113
TM1194A Issue B Page 1 - 5
Operational Environment
8. The environmental characteristics of the BSR 113 are as follows:
a) Operational Temperature Range: -25(C to +55(C b) Humidity: Up to 95% Relative Humidity over the
operational temperature range
c) Stability: ±6ppm over the operational temperature
range
BSR 113
TM1194A Issue BPage 1 - 6
INTENTION ALLY BLANK
BSR 113
TM1194A Issue B Page 2 - 1
SECTION 2
OPERATING INSTRUCTIONS
CONTENTS:
1. OPERATION
_______________________
OPERATION
1. The BSR 113 is automatic in operation, with the exception of the following:
a) Switching on the power supply. b) Setting the volume control (located at the rear of the unit) to a suitable level.
BSR 113
TM1194A Issue BPage 2 - 2
INT ENTIO NALL Y BLAN K
BSR 113
TM1194A Issue B Page 3 - 1
SECTION 3
TECHNICAL DESCRIPTION
CONTENTS:
1. INTRODUCTION
RADIO CIRCUITRY
2. Signal Input and Isolation
3. RF Amplifier and Filters
4. First Local Oscillator
6. First Mixer
7. Second Local Oscillator and Mixer
8. Second IF Stage
9. Audio Splitting
RX AUDIO PATH
10. Filtering and Amplification
11. Speaker Audio
12. Line Out Driver
NOISE SQUELCH PATH
15. Filtering and Amplification
18. Schmitt Monostable
20. Signal Logic Levels
21. Signal Indication and Noise Squelch Defeat
22. Signal Detect Reed Relay
23. Signal Strength Tone Circuitry
26. Tone Out Driver
SUB-AUDIO TONE PATH
29. Filtering and Amplification
30. Sub-Audio Tone Decoder
32. Sub-Audio Tone Indication and Disable
33. Sub-Audio Tone Squelch Delay Circuit
35. DATA PATH
POWER SUPPLIES
36. +12V Supply
37. +10V Regulator
38. +5V Regulator
39. +1V Internal Reference
BSR 113
TM1194A Issue BPage 3 - 2
TABLES Page
1. Noise Squelch Signal Levels 3-8
2. Sub-Audio Tone Frequency Adjustments 3-10
FIGURE
1. Functional Block Diagram 3-2
_______________________
INTRODUCTION
1. This section provides a technical description of the BSR 113 circuit operation. Reference should be made to the functional block diagram (Figure 1) and the circuit diagrams in Section 7.
RADIO CIRCUITRY
Signal Input and Isolation
2. The incoming RF signal is detected by an external antenna connected to socket SK7, from where the signal passes through an isolating transformer (T1) which improves immunity to Electro-Static Discharge (ESD). The signal is then fed to the first RF helical fi lter, FL11, which protects the RF amplifier fro m str ong out-of­band signals.
RF Amplifier and Filters
3. Impedance matching is provided by L15, L16 and associated components. The RF signal is amplified by TR3 and then fil tered by the helical fil ters FL8, FL9 and FL10. They provide a degree of selectivity before passing the signal to the first mixer.
First Local Oscillator
4. The first local oscillator comprises TR1, XL1 and associated components. Frequency adjustment is provided by C3. The collector o f TR1 is t uned to the third harmonic of XL1 by C9 and L6. The output of TR1 is then doubled by TR2 to provide the correct injection frequency for the first mixer.
5. The frequency of the crystal is calculated by using the following formula: Crystal (XL1) frequency (MHz) = Receiver Channel Frequency (MHz) - 45MHz
6
BSR 113
TM1194A Issue B Page 3 - 3
Figure 1: Functional Block Diagram
BSR 113
TM1194A Issue BPage 3 - 4
First Mixer
6. The first mixer comprises TR6 and associated components. The i njecti on fr equency from the first local oscillator is fed to the first mixer via the helical filter FL7 and inductor L9. The RF signal is input via the inductor L13. The difference signal of 45MHz is selected by the collector load of L12, R18 and C29. The 45MHz is then filtered by FL1 and FL2 to remove unwanted signals.
Second Local Oscillator and Mixer
7. The second local oscillator is formed by TR4, XL2 and associated components. It runs at a fixed frequency of 44.545MHz. The signal is selected from the collector of TR4 and input, along with the RF from FL2, onto the base of mixer TR5. The difference signal of 455kHz then passes to FL5, with matching provided by R31.
Second IF Stage
8. The second IF chain comprises three ceramic filters of channel bandwidt h, FL5 , FL6 and FL4, each followed by an IF amplifier. After FL5 the 455kHz IF signal is amplified by the low noise transistor TR25 and then passed to FL6. The signal is then fed to IC1 (pin 1) where the r emaining IF amplifi cation and amplitude limiting are provided. Another stage of filtering is carried out by FL4. Demodulation is carried out using the ceramic discriminator FL3 as the quadrature network for the on-chip demodulator. After demodulation the signal is output from IC1 (pin 14).
Audio Splitting
9. The demodulated audio signal leaves IC1 (pin 14) and divides three ways: a) To a de-emphasis circuit (comprising R339 and C104) and the Rx Audio path. b) To a de-emphasis circuit (comprising R365 and C154) and the Noise Squelch
path.
c) To an active fi lter (comprising TR24, C82, C83, R341 and R344) where it then
divides two ways: i) To the Sub-Audio Tone path. ii) To the Data path.
BSR 113
TM1194A Issue B Page 3 - 5
RX AUDIO PATH
Filtering and Amplification
10. The audio si gnal is de-emphasised by R339 and C104 to produce the test and tune
up signal Audio X (available at the i nternal test socket SK5 pin 2) . It also passes through two stages of high pass filtering and two stages of low pass filtering, provided by IC11 (pin 8) and IC11 (pin 14), to become the Rx Audio signal. The fitting of link LK4 enables the signal to bypass the high pass filter stage IC11 (pin
1) (for future applications). IC11 (pin 7) acts as a buffer amplifier.
Speaker Audio
11. The Rx Audio output from IC11 (pin 14) is fed, via the audio gate TR13, to the
input of an operational-amplifier circuit, IC10, via R93 and RV4. Variable resistor RV4 provides volume control. The speaker driver uses a bridge technique to provide maximum voltage swing on the speaker driver output. Resistors R168, R169, R170 and R171 are load protection for IC10 to prevent any damage to the chip resulting from over dissipation.
Line Out Driver
12. The Rx Audio output from IC11 (pin 14) is also fed, via the audio gate TR23 and
RV6, to the Line Out driver amplifier IC8. In normal operation link LK2 i s fitted and the Line Out signal is gated by the noise Squelch, via gate TR18. Alt ernati vely, the signal can be continuously enabled by removing link LK2.
13. The output of IC8 (pin 1) is passed to the l ine termination loading and safe ty bar rier
circuitry provided by components R104, R105, R106, R107, R108, R109, C242, C243, C244, CS4 and T4. The Line Out signal then proceeds to the external line connection via SK2 (pins 4 and 6).
14. The links LK22, LK23, LK24, and LK25 are intended for setting the Line Out
termination loading when connecting to Public Telephone Operator (PTO) lines in different countries (subject to national li ne connection approval). For further details refer to Section 4. In normal operation Link LK5 is fitted and is removed only for factory test purposes. The Tone Out signal is combined with the Line Out signal by the fitting of link LK10 (refer to Section 4).
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