Philips SPENDEX 40 User manual

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NATO Confidential
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SPEECH ENCRYPTION DECRYPTION EQUIPMENT
TYPE UA 0251/00 and /Ol
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Limited Maintenance Manual
PHILIPSUSFABV
NATO Confidential
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Document No. 9922 154 13431
Issue date: 29-09-88
Printed in The Netherlands
All rights strictly reserved. Reproduction or issue to third parties, in any form whatsoever, is not
permitted without the written consent of the proprietors. In addition Philips Usfa B.V. Eindhoven.
The Netherlands, reserve the right to make modifications and improvements in their design
without prior notice.
Philips Usfa B.V.
Tel: [phone]
P.O Box 218 5600 MD Eindhoven, The Netherlands
Te l e x : 5 1 7 3 2 U S FA E N L F a x . ( 0 4 0 ) 7 2 3 6 5 8
PHILIPS
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CONTENTS
Page
C o n t e n t s i
L i s t o f fi g u r e s i i
Abbreviations iii
Definitions iii
L i s t o f E f f e c t i v e P a g e s i i i
1 I N T R O D U C T I O N 1 - 1
1 . 1 G e n e r a l 1 - 1
1 . 2 T e c h n i c a l d e s c r i p t i o n 1 - 1
1 . 3 M e c h a n i c a l c o n s t r u c t i o n 1 - 1
2 T E C H N I C A L D A T A 2 - 1
3 M O D U L A R S E T - U P 3 - 1
3 . 1 M a i n a s s e m b l y 3 - 1
3 . 2 A c c e s s o r i e s 3 - 5
4 C I R C U I T D E S C R I P T I O N 4 - 1
4 . 1 H a n d s e t 4 - 1
4 . 2 F r o n t p a n e l 4 - 2
4 . 3 C o n n e c t i n g b o a r d 4 - 3
4 . 4 S y n t h e s i s b o a r d 4 - 5
4 . 5 A n a l y s i s b o a r d 4 - 7
4 . 6 K e y m e m o r y b o a r d 4 - 8
4 . 7 K e y g e n e r a t o r b o a r d 4 - 9
4 . 8 C o n t r o l l e r b o a r d 4 - 1 1
4.9 Timing board 4-12
4.10 Telephony board 4-13
4 . 1 1 V 2 6 / V 2 6 b i s m o d e m 4 - 1 4
4 . 1 2 V 2 2 b i s m o d e m 4 - 1 4
4.13 Line interface board 4-15
4.14 Cradle/upper cover 4-17
4 . 1 5 M a i n s / l i n e fi l t e r 4 - 1 7
4.16 Power supply unit 4-17
5 H A R D W A R E S E T T I N G S 5 - 1
6 F A U L T F I N D I N G A N D R E P A I R P R O C E D U R E 6 - 1
6 . 1 G e n e r a l 6 - 1
6 . 2 S e l f - t e s t 6 - 2
6 . 3 S e t - u p t e s t 6 - 6
6 . 3 . 1 T e s t s t a r t p r o c e d u r e 6 - 6
6 . 3 . 2 K e y b o a r d / d i s p l a y t e s t 6 - 7
6 . 3 . 3 S w i t c h t e s t 6 - 9
6 . 3 . 4 M e m o r y t e s t 6 - 1 0
6 . 3 . 5 M o d e m t e s t 6 - 1 1
6 . 3 . 6 V o c o d e r t e s t 6 - 1 2
6 . 3 . 7 T i m e r t e s t 6 - 1 3
6 . 3 . 8 S y s t e m t e s t 6 - 1 4
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Page
7 D E M O U N T I N G A N D M O U N T I N G 7 - 1
7 . 1 G e n e r a l 7 - 1
7 . 2 R e p l a c e m e n t o f t h e b a t t e r y 7 - 1
7 . 3 D e m o u n t i n g 7 - 1
7 . 4 M o u n t i n g 7 - 6
7.5 Adjustment of the transmission level 7-10
LIST OF FIGURES
M o d u l a r s e t - u p S P E N D E X 4 0 3 - 7
B l o c k d i a g r a m S P E N D E X 4 0 ( p a r t 1 ) 4 - 1 8
B l o c k d i a g r a m S P E N D E X 4 0 ( p a r t 2 ) 4 - 1 9
B l o c k d i a g r a m S P E N D E X 4 0 ( p a r t 3 ) 4 - 2 0
D e f a u l t s e t t i n g s y n t h e s i s b o a r d 5 - 9
Default setting timing board 5-10
D e f a u l t s e t t i n g s V 2 6 / V 2 6 b i s m o d e m 5 - 1 1
Default settings V22bis modem 5-12
D e f a u l t s e t t i n g s l i n e i n t e r f a c e b o a r d 5 - 1 3
M a i n s v o l t a g e s e t t i n g 5 - 1 4
F a u l t fi n d i n g d i a g r a m S P E N D E X 4 0 6 - 1 6
F a u l t fi n d i n g d i a g r a m S P E N D E X 4 0 ( c o n t i n u e d ) 6 - 1 7
F a u l t fi n d i n g d i a g r a m S P E N D E X 4 0 ( c o n t i n u e d ) 6 - 1 8
Front view of the housing 7-12
B a c k v i e w o f t h e h o u s i n g 7 - 1 3
T o p v i e w o f p o w e r s u p p l y c o m p a r t m e n t 7 - 1 4
Fig. 3.1
Fig. 4.1
Fig. 4.2
Fig. 4.3
Fig. 5.1
Fig. 5.2
Fig. 5.3
Fig. 5.4
Fig. 5.5
Fig. 5.6
Fig. 6.1
Fig. 6.2
Fig. 6.3
Fig. 7.1
Fig. 7.2
Fig. 7.3
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?Abbreviations
C I K C r y p t o I g n i t i o n K e y
C K G C h e c k K e y G e n e r a t o r
IVSN Initial Voice Switched Network
K D C K e y D i s t r i b u t i o n C e n t r e
P K G P r i m a r y K e y G e n e r a t o r
P t t P r e s s t o t a l k
R K G R e c e i v e K e y G e n e r a t o r
STU-II Secure Telephone Unit (second generation)
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Definitions
CIK-module:
Programmed module, unique per terminal, required for crypto operation.
Full Duplex:
Mode of transmission in which at both ends of a connection data are transmitted
and received simultaneously.
Half Duplex:
Mode of transmission in which alternately data are transmitted at one end of a
connection and received at the other.
KDC mode:
Encryption mode in which KDC call variables are used.
Net mode:
Encryption mode in which Net variables are used.
Pulse Dialling:
Dialling mode in which during the dialling of a telephone number a series of
pulses is transmitted for each digit.
Secure Telephone Unit:
Speech Encryption/Decryption Equipment of the type TSEC/KY-71A.
Tone Dialling:
Dialling mode in which during the dialling of a telephone number 2 tones with
a different frequency are transmitted for each digit.
List of Effective Pages
Page numbers: i to iii
1- 1
2- 1 to 2- 3
3- 1 to 3- 7
4- 1 to 4-20
5- 1 to 5-14
6- 1 to 6-18
7- 1 to 7-14
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1 INTRODUCTION
1.1 General
This manual contains instructions for the limited maintenance of the
speech encryption/decryption equipment SPENDEX 40, types UA 8251/00
and UA 8251/01. The fault finding and repair procedures are
restricted to the location and replacement of defective exchangeable
units, if any.
1.2 Technical description
The speech encryption/decryption equipment SPENDEX 40 is an apparatus
with which it is possible to achieve secure communication (speech and
data) via telephone lines and radio contacts. For secure
communication via telephone lines the apparatus is provided with an
internal line modem, whereas for secure communication via radio
contacts a special radio modem need to be connected. The SPENDEX 40
can also be used as a normal telephone for nonsecure communication.
SPENDEX 40 can operate in Pulse Dialling and Tone Dialling mode. With
an appropriate network it is possible to set up in the Tone Dialling
mode a connection with a certain precedence level. In this case a
choice can be made of 4 different levels, viz. priority, immediate,
flash and flash override.
SPENDEX 40, type UA 8251/00, is equipped with a V26/V26bis modem.
With an apparatus of this type it is possible to achieve secure
communication in the 2-wire Half Duplex or in 4-wire Full Duplex
transmission mode. A type UA 8251/00 apparatus can operate in the Net
and KDC mode. In the KDC mode and in the NET mode, but only with a
key variable in compartment 00, an apparatus can cooperate with a
STU-II unit (Secure Telephone Unit, second generation).
SPENDEX 40, type UA 8251/01, is fitted with a V22bis modem. With this
type of equipment secure communication can be achieved in the 2-wire
Full Duplex transmission mode. An UA 8251/01 apparatus can only
operate in the Net mode.
Remark: equipment types UA 8251/00 and UA 8251/01 cannot cooperate
with each other in any mode whatsoever.
1.3 Mechanical construction
SPENDEX 40 is a compact apparatus built up of modules and is
primarily designed for office use. For mobile use a shock mounting is
available.
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TECHNICAL DATA
2.1 Identification
Name
Type
Manufacturer
Speech Encryption/Decryption Equipment SPENDEX 40
UA 8251/00 or UA 8251/01
Philips Usfa B.V., Eindhoven
2.2 Speech digitising
Linear Predictive Coding (LPC-10) according to STANAG 4198
g2.3 Data interface
Signal level: according to CCITT-recommendation V24/V28 or
EIA-standard RS232-C
Bit rate : 2400 bit/s
2 . 4 M o d e m i n t e r f a c e
** Signal level: according to CCITT-recommendation V24/V28
Bit rate : 2400 bit/s
2.5 Line interface
Speech:
- s i g n a l f o r m : a n a l o g u e
- frequency range : 80...3400 Hz
Data (equipment type UA 8251/00):
- sign a l level
- bi t ra te
- transmission rate
- carrier frequency
- transmission level
- reception level
according to CCITT-recommendation V26/V26bis
2400 bit/s
1200 Bd
1800 Hz
adjustable from -23 dB to +4 dB
-43 dB to 0 dB
Data (equipment type UA 8251/01):
according to CCITT-recommendation V22bis
2400 bit/s
600 Bd
1200 Hz (low channel)
2400 Hz (high channel)
- transmission level: adjustable from -24 dB to +6 dB
- reception level : -45 dB to 0 dB
- sign a l level
- bi t ra te
- transmission rate
- carrier frequency
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2.6 Setting possibilities
Possibility of Half Duplex or Full Duplex transmission mode:
- equipment type UA 8251/00: HD or FD
- equipment type UA 8251/01: FD only
Adjustment of the synchronisation to the internal or external modem:
LF/HF
Adaptation to 2-wire or 4-wire connection:
- equipment type UA 8251/00: 2W or 4W
- equipment type UA 8251/01: 2W only
Choice between Pulse Dialling or Tone Dialling: PD/TD
Adjustment of the ringing signal volume: RV1...RV4
2 . 7 P o w e r s u p p l y
Mains voltage
Power consumption
Fuses
2.8 Batterv
110 V or 220 V ± 15%, 47...63 Hz
45 W max.
2 x 110 V/l A slow or 2 x 250 V/500 mA slow
Type :3.9V penlight UA 6303/03
Voltage : 3.5...4.5 V
2.9 Environmental conditions
Temperature:
- i n o p e r a t i o n : - 1 0 ° C t o + 5 0 ° C
- during storage and transport : -40°C to +70°C
Relative humidity:
- i n o p e r a t i o n : u p t o 9 0 %
- during storage and transport : up to 95%
Radiation:
- TEMPEST approved according to AMSG-720B
- the equipment meets the EM-demands according to MIL-STD-461B
Vibration/shock:
When mounted on the shock mounting type UA 8254/00 the equipment
meets the vibration and shock demands according to DEF STAN 07-55
- vibration, test A2
- shock, test A5
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2.10 Physical properties
Dimensions : 38.5 cm x 27 cm x 16/23 cm
Weight : approx. 12 kg
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3 MODULAR SET-UP (see Fig. 3.1)
3.1 Main assembly
3.1.1 Front panel UA 8312/00
The front panel contains:
- the handset connector
- the data connector
- the fill-gun connector
- the CIK-connector
- the ZEROISE push button
- the SECURE push button
- the keyboard
Furthermore the front panel is provided with 3 filter plates:
- a filter plate (display, keyboard), consisting of the display and
keyboard panel with display, LED and feed-through filters for the
signals from and to the keyboard interface, the display interface
and the LED;
- a filter plate (switches) with feed-through filters for the sign a l s
from and to the ZEROISE push button and the SECURE push button;
- a filter plate (handset, data, CIK, fill-gun) with feed-through
filters for the signals from and to the handset, a Data Terminal
Equipment, the CIK-module and a key variable loading device.
3.1.2 Housing UA 8311/00
The housing consists of 3 compartments:
- the red compartment
- the line interface compartment
- the power supply compartment
On the bottom of the red compartment the mother board has been
mounted. This mother board is fitted with connectors for the
connection of the connecting board, the synthesis board, the analysis
board, the key memory board, the key generator board, the controller
board, the timing board and the telephony board.
The line interface compartment accommodates the modem and the line
interface board.
The power supply unit is in the power supply compartment.
The housing has 3 filter plates:
- a filter plate (modem/pr.mod.) with feed-through filters for the
signals from the mother board to the line interface board and for
the signals from the line interface board to the mother board;
- a filter plate (power supply/pr.mod.) with feed-through filters for
the power supply voltages to the mother board;
- a filter plate (power supply/modem) with feed-through filters for
the power supply voltages to the line interface board.
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3.1.3 Connecting board UA 8310/00
The connecting board contains:
- the microphone amplifier
- the low pass filter transmitting side
- the A/D-converter
- the D/A-converter
- the low pass filter receiving side
- the telephone amplifier
- the CIK-interface
- th e fi l l -g un i n t e rf ac e
- the CCITT-V28/EIA RS232 data interface
- a clear/secure relay
- the analogue-loop relay
- a +12/+5 V power converter
- a -12/-5 V power converter
- a zeroise switch
3 . 1 . 4 S y n t h e s i s b o a r d U A 8 3 2 3 / 0 0
The synthesis board contains:
- the DFT-processor
- the pitch processor
- synthesis processor 1
- synthesis processor 2
- the vocoder controller
- the vocoder program memory
- the vocoder data memory
- the vocoder address decoder
- a timi n g circui t
- the master clock signal generator
3 . 1 . 5 A n a l y s i s b o a r d U A 8 3 2 2 / 0 0
The analysis board contains:
- the segmentation buffer
- the pitch buffer
- the speech buffer
- the analysis processor
- a tim ing circuit
- the slave clock signal generator
3 . 1 . 6 K e y m e m o r y b o a r d U A 8 3 2 1 / 0 0
The key memory board contains:
- program memory 2 (U EPROM)
- the zeroise memory
- the key variable memory
- the zeroise circuit
- a zeroise switch
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3 . 1 . 7 K e y g e n e r a t o r b o a r d U A 8 3 2 0 / 0 0
The key generator board contains:
- the series/parallel converter for the data signal to be encrypted
originating from the Data Terminal Equipment
- the key generators transmitting side (PKG/CKG)
- the parallel/series converter for the data signal to be transmitted
- the series/parallel converter for the received data signal
- the key generator receiving side (RKG)
- the parallel/series converter for the decrypted data signal
destined for the Data Terminal Equipment
- the alarm circuit
3.1.8 Controller board UA 8319/00
The controller board contains:
- the comsec controller
- program memory 1 (M EPROM)
- the data memory red
- the data memory black
- the address decoder
- t h e i n t e r r u p t c i r c u i t
3.1.9 Timing board UA 8318/00
The timing board contains:
- the time base
- timer long
- timer short
- the alarm and power-on reset circuit
!
3.1.10 Telephony board UA 8317/00
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The telephony board contains:
- the dialling tone generator
- the dialling pulse generator
- the 2025/2100 Hz answering tone detector
- the 420 Hz pre-emption signal detector
- the on/off-hook detector
- internal-loop switches
3 . 1 . 1 1 V 2 6 / V 2 6 b i s m o d e m U A 8 3 1 4 / 0 1
ONLY IN EQUIPMENT TYPE UA 8251/00
The V26/V26bis modem modulates the signal to be transmitted and
demodulates the received signal according to CCITT-recommendation
V26/V26bis.
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3.1.12 V22bis modem UA 8343/00
ONLY IN EQUIPMENT TYPE UA 8251/01
The V22bis modem modulates the signal to be transmitted and
demodulates the received signal according to CCITT-recommendation
V22bis.
3.1.13 Line interface board UA 8316/00
The line interface board contains:
- the line output amplifier
- the line input amplifier
- the internal/external modem selector
- the CCITT-V28 modem interface
- the ringing signal detector
- a clear/secure relay
- the external-loop relay
- the 2-wire/4-wire switching relay
- the on-hook relay
- 2 dialling pulse relays
3.1.14 Upper cover UA 8307/00
The upper cover covers the upper side of the red compartment of the
housing. In this upper cover also the reed contact of the hook switch
is mounted.
3.1.15 Cradle UA 8313/00
The cradle accommodates the handset. The switch arm of the hook
switch is mounted in the cradle.
3 . 1 . 1 6 M a i n s / l i n e fi l t e r ( b a c k c o v e r ) U A 8 3 0 9 / 0 0
The mains/line filter contains:
- the on/o ff-switch
- the earth connection
- the mains connection with 2 fuse holders
- the line connector
- the modem connector
Furt hermo r e the mai ns/li n e filter i s fitted w i th:
- a transformer panel with 2 transformers which take care of a
galvanic separation with the line;
- a filter plate (line/modem) with feed-through filters for the
signals from and to the line and an external modem;
- a filter plate (battery) consisting of a battery compartment with
fee d-through filters for the battery voltage;
- a protection panel (mains) and 2 feed-through filters for the
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110/220 V mains supply voltage.
3.1.17 Power supply unit UA 8308/00
The power supply unit converts the 110/220 V mains supply voltage
into supply voltages of +5 V, +12 V and -12 V.
3.2 Accessories
3.2.1 Handset UA 8252/00
The handset contains the microphone, the telephone and the Ptt
(Press-to-talk)-switch. The Ptt-switch need only be used with the
type UA 8251/00 equipment during a secure conversation in the Half
Duplex transmission mode.
3.2.2 CIK-module UA 8247/00
The CIK-module is a module, provided with the Crypto Ignition Key,
which is required to let the equipment operate in a secure mode.
Without the CIK-module the apparatus can only be used as a normal
telephone for nonsecure communication. The Crypto Ignition Key is
stored in an EEPROM and is also maintained there when the CIK-module
is not connected to the apparatus. The CIK-module does not contain a
battery.
3 . 2 . 3 B a t t e r y U A 6 3 0 3 / 0 0
3.9V nonrechargeable lithium battery which sees to it that the
contents of the key memory and the zeroise memory remain preserved in
case of a power breakdown or when the equipment is switched off. The
battery is not charged when the apparatus is switched on.
3.2.4 Fuses
For 220 V:
- 2 x 2 5 0 V / 5 0 0 m A s l o w 2 4 2 2 0 8 6 0 1 0 1 5
For 110 V:
- 2 x 1 1 0 V / l A s l o w 2 4 2 2 0 8 6 0 1 0 2 1
3.2.5 IVSN-line connecting cable UA 8240/01
Line connecting cable to connect a type UA 8251/00 equipment to the
NATO-IVSN network.
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3.2.6 PTT-line connecting cable UA 8240/00
Line connecting cable to connect an apparatus to a public PTT
network.
3.2.7 Mains supply cable 5722 660 30670
Supply cable to connect the 110/220 V mains supply voltage.
3 . 2 . 8 S h o c k m o u n t i n g U A 8 2 5 4 / 0 0
IShock mounting for use of the equipment in rooms, which are not
vibration-free.
3.2.9 Transport case UA 8342/00
Special case to transport the equipment.
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4 CIRCUIT DESCRIPTION
This chapter gives a functional description of the various circuits.
The circuits are described per module on the basis of the block
diagrams of Fig. 4-1, Fig. 4-2 and Fig. 4-3.
4.1 Handset
4.1.1 Microphone
The microphone converts the speech signal into an electric signal.
The signal thus obtained is directed to the microphone amplifier on
the connecting board.
4.1.2 Telephone
The telephone makes the signal, which comes from the telephone
amplifier on the connecting board, audible.
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The Ptt-switch should be used during a secure conversation in the
Half Duplex transmission mode (equipment type UA 8251/00). Every time
the Ptt-switch is pressed, the Ptt-signal is activated.
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4.2 Front panel
4.2.1 ZER O IS E pu sh b utton
As soon as the ZEROISE push button is pressed, the signals ZER01N and
ZER02N are activated. The signal ZER01N is passed on to the comsec
controller and the signal ZER02N to the zeroise circuit on the key
memory board.
4.2.2 SECURE push button
As soon as the SECURE push button is pressed, the signals CLRSC1 and
CLRSC2 are activated. The signal CLRSC1 is passed on to the comsec
controller and the signal CLRSC2 energises the clear/secure relay RE3
on the connecting board.
4.2.3 Keyboard
The keyboard contains 16 keys.
4.2.4 Keyboard interface
The keyboard interface takes care of the coupling between the comsec
controller and the keyboard. Moreover the interface makes an
interrupt signal INTKEY every time a key is pressed.
4 . 2 . 5 D i s p l a y a n d L E D
The alphanumerical display with 8 characters, as well as the LED are
situated behind a window over the keyboard. The LED is to the right
of the display and is controlled by the comsec controller.
4 . 2 . 6 D i s p l a y i n t e r f a c e
The display interface takes care of the coupling between the comsec
controller and the display.
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4.3 Connecting board
4.3.1 Microphone amplifier
This amplifier amplifies the analogue signal which comes from the
microphone.
4 . 3 . 2 L o w p a s s fi l t e r t r a n s m i t t i n g s i d e
The low pass filter transmitting side is the first circuit on the
transmitting side of the vocoder. The filter limits the frequency
band of the amplified microphone signal to approx. 3600 Hz.
4.3.3 A/D-converter
The A/D-converter samples the signal limited in band width with a
frequency of 8 kHz and converts each sample into an a-law code of 8
bits.
4.3.4 D/A-converter
The D/A-converter converts the digital signal, which comes from
synthesis processor 2 on the synthesis board, again into an analogue
signal.
4 . 3 . 5 L o w p a s s fi l t e r r e c e i v i n g s i d e
The low pass filter receiving side is the last circuit on the
receiving side of the vocoder. The filter limits the frequency band
of the analogue signal to approx. 3600 Hz.
4.3.6 Telephone amplifier
This amplifier amplifies the signal destined for the telephone. This
signal can be the output signal of the vocoder limited in band width,
the output signal of the line input amplifier, the ringing signal,
the output signal of the dialling tone generator or the pre-emption
signal.
4.3.7 CIK-interface
The CIK-interface takes care of the coupling between the equipment
and the CIK-module. When the CIK-module is removed at a moment that
the apparatus is in a state, in which the CIK-module should be
connected, the interface will produce a CIK-alarm (CIKAL).
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4.3.8 Fill-gun interface
This interface takes care of the coupling between the equipment and a
key variable loading device. When the key variable loading device is
removed at a moment that the equipment is in a state, in which the
key variable loading device should be connected, the interface will
produce a FILL-alarm (FILAL).
4.3.9 Data interface
The data interface takes care of the coupling between the equipment
and a Data Terminal Equipment in accordance with CCITT-recommendation
V24/V28 or EIA-standard RS232-C.
4.3.10 Clear/secure relay
The clear/secure relay RE3 is energised as soon as the SECURE push
button is pressed or the comsec controller activates the
CLRSEC-signal. The comsec controller will activate the CLRSEC-signal
after the other party has pressed the SECURE push button.
4.3.11 Analogue-loop relay
For test purposes the comsec controller can energise the
analogue-loop relay RE2 by means of the STRE2-signal, as a
consequence of which (if clear/secure relay RE3 is energised) the
vocoder output is connected with the vocoder input.
4.3 .12 P o wer s upp l y con ver t ers
The power supply converters convert the +12 V and -12 V supply
voltages into supply voltages of +5 V and -5 V for a number of
analogue circuits.
4.3.13 Zeroise switch
As soon as the front panel is removed the zeroise switch is opened,
as a consequence of which the zeroise circuit on the key memory board
is ac t ivat ed.
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4 . 4 S y n t h e s i s b o a r d
4.4.1 DFT-processor
Every 22.5 ms the contents of the segmentation buffer on the analysis
board are presented 128 times to the DFT-processor. The DFT-processor
determines the spectrum by means of a Discrete Fourier Transformation
and passes the result on to the pitch processor in serial form.
4.4.2 Pitch processor
Via an harmonic filtering method the pitch processor determines the
pitch from the amplitude peaks of the spectrum. As soon as the pitch
processor has calculated the pitch, the vocoder controller will be
interrupted (INTPIT). After acceptation of the interrupt the vocoder
controller will take over the pitch, smooth it and store it in the
pitch buffer of the analysis board.
4 . 4 . 3 S y n t h e s i s p r o c e s s o r 1
The moment synthesis processor 1 is ready to receive a frame, the
vocoder controller is interrupted (INTSYN); then the vocoder
controller collects the oldest frame from the synthesis part of the
vocoder data memory and passes it on to synthesis processor 1. As
soon as synthesis processor 1 has received the frame, the first part
of the synthesis starts. When the signal NFRN is activated synthesis
processor 1 is interrupted. After acceptation of the interrupt the
results are sent to synthesis processor 2.
4 . 4 . 4 S y n t h e s i s p r o c e s s o r 2
Synthesis processor 2 generates the 8 bit samples initially coded in
a-law. Then the samples will be passed on in serial form to the
D/A-converter on the connecting board.
4 . 4 . 5 V o c o d e r c o n t r o l l e r
The vocoder controller takes care of the control of the vocoder and
exchanges via the vocoder bus system data and control signals with
the various circuits within the vocoder.
Furthermore the vocoder controller looks on transmitting side after
the transfer of frames to the comsec controller and on receiving side
after the take-over of frames from the comsec controller.
After acceptation of the interrupt signal INTCO, which comes from the
comsec controller, the vocoder controller will collect a frame to be
sent from the analysis part of the vocoder data memory and transfer
this frame to the comsec controller or take over a received frame
from the comsec controller, correct its errors, if any, and then
store it in the synthesis part of the vocoder data memory.
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4.4.6 Vocoder program memory
This program memory (32,768 x 8 bit) contains the firmware for the
vocoder controller.
4. 4. 7 Vo c od er d ata m em or y
The vocoder data memory consists of a 2048 x 8 bit memory. The
vocoder controller uses this memory for the temporary storage of
data. Part of the data memory, the analysis part, is used for the
storage of frames on the transmitting side. Another part, the
synthesis part, is used for the storage of frames on the receiving
side.
4.4.8 Vocoder address decoder
This address decoder takes care of the addressing of the various I/O'
and memory locations within the vocoder.
4.4.9 Timing circuit
The timing circuit generates several timing signals for the control
of the various circuits within the vocoder.
4. 4.1 0 Mas te r c lo ck si gna l ge n er ato r
The master clock signal generator produces clock signals of 8192 kHz,
4096 kHz, 2048 kHz and 512 kHz. The clock signals control various
circuits within the vocoder. The 4096 kHz clock signal also controls
the comsec controller on the controller board and the key generators
on the key generator board.
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