AnyDATA DTS-800 CDK User manual

CDMA Development Kit
DTS-800 CDK
AnyDATA.NET Inc.
Hanvit Bank B/D 7F
Byulyang-dong Kwachon
KOREA
Tel) 82-2-504-3360
Fax) 82-2-504-3362
SERVICE MANUAL

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Introduction
The CDMA development kit (CDK -800) is designed for the test and simulation of the CDMA wireless data
communications. User can connect the development kit to your PC or Notebook and easily test the wireless
communications. User can use this to develop your applications software even before user’s own hardware is
ready. It also can be used as a debugging during user’s hardware test.
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Disclaimer and Limitation of Liability
AnyDATA.NET Inc. assumes no responsibility for any damage or loss resulting from the misuse of its products.
AnyDATA.NET Inc. assumes no responsibility for anyloss or claims bythird parties, which may arise through the
use of its products. AnyDATA.NET Inc. assumes no responsibility for any damage or loss caused by the deletion
or loss of data as a result of malfunctions or repairs.
The information disclosed herein is the exclusive property of AnyDATA.NET Inc. and no part of this publication
may be reproduced or transmitted in any form or by any means including electronic storage, reproduction,
adaptation , translation , execution or transmission without the prior written consent of AnyDATA.NET Inc.
The information contained in this document is subject to change without notice.
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FCC RF Exposure Information
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Warning!
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Read this information before using this device.
In August 1996 the Federal Communications
Commission (FCC) of the United States with its action in Report and Order FCC 96-326
adopted an updated safety standard for human exposure to radio frequency electromagnetic
energy emitted by FCC regulated transmitters. Those guidelines are consistent with the safety
standard previously set by both U.S. and international standards bodies. The design of this
device complies withthe FCC guidelines and these international standards.
CAUTION

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Operating Requirements
The user can not make any changes or modifications not expressly approved by the party responsible for
compliance, otherwise it could void the user's authority to operate the equipment.
To satisfy FCC RF exposure compliance requirements for a mobile transmitting device, this device and
its antenna should generally maintain a separation distance of 20cm or more froma person’s body.
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Special accessories
In order to ensure this device in compliance with FCC regulation, the special accessories are provided with this
device and must be used with the device only. The user is not allowed to use any other accessories than the special
accessories given with this device
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Table of Contents

General Introduction
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CHAPTER 1. System Introduction
1. System Introduction ......................................................................................................... 3
2. Features and Advantages of CDMA Module .................................................................. 4
3. Structure and Functions of CDMA Module ..................................................................... 7
4. Specification ..................................................................................................................... 8
CHAPTER 2. NAM Input Method(Inputting of telephone numbers included)
1. NAM Programming Method and Telephone Number Input Method ..............................11
CHAPTER 3. Circuit Description
1. Overview.......................................................................................................................... 14
2. RF Transmit/Receive Part .............................................................................................. 14
3. Digital/Voice Processing Part ...................................................................…….. 17
CHAPTER 4. FCC Notice
Appendix
........................................................................................................................................ 22
1. Assembly and Disassembly Diagram
2. Block & Circuit Diagram
3. Part List
4. Component Layout

The DTS-800 CDK functions digital cellular module worked in CDMA (Code Division Multiple
Access) mode. CDMA type digital mode applies DSSS (Direct Sequence Spread Spectrum) mode
which is used in military.
This feature enables the phone to keep communication from being crossed and use one frequency
channel by multiple users in the same specific area, resulting that it increases the capacity 10 times
more compared with that in the analog mode currently used.
Soft/Softer Handoff, Hard Handoff, and Dynamic RF power Control technologies are combined into
this phone to reduce the call being interrupted in a middle of talking over phone.
CDMA digital cellular network consists of MSC (Mobile Switching Office), BSC (Base Station
Controller), BTS (Base station Transmission System), and MS (Mobile Station). Communication
between MS and BTS is designed to meet the specification of IS-95A (Common Air Interface). MS
meets the specifications of the below :
- IS-95A ( Common Air Interface ) : Protocol between MS and BTS
- IS-96A ( Vocoder ) : Voice signal coding
- IS-98 : Basic MS functions
- IS-126 : Voice loopback
- IS-99 : Short Message Service, Async Data Service, and G3 Fax Service
DTS-800 CDK is
digital mode is designed to be operated in full duplex.
General Introduction

DTS-800
1. System Introduction
1.1 CDMA Abstract
The cellular systemhas a channel hand-off function that is used for collecting the information on the locations and movements of
radio mobile telephones from the cell site by automatically controlling several cell site through the setup of data transmission
routes and thus, enabling one switching system to carry out the automatic remote adjustment. This is to maintain continuously the
call state through the automatic location confirmation and automatic radio channel conversion when the busy subscriber moves
from the service area of one cell site to that of another by using automatic location confirmation and automatic radio channel
conversion functions. The call state can be maintained continuously by the information exchange between switching systems when
the busy subscriber moves fromone cellular systemarea to the other cellular systemarea.
In the cellular system, the cell site is a small-sized low output type and utilizes a frequency allocation system that considers
mutual interference, in an effort to enable the re-use of corresponding frequency from a cell site separated more than a certain
distance. The analog cellular systems are classified further into an AMPS system, E-AMPS System, NMT system, ETACS
system, and JTACS systemdepending on technologies used.
Unlike the time division multiple access (TDMA) or frequency division multiple access (FDMA) used in the band limited
environment, the Code Division Multiple Access(CDMA) system which is one of digital cellular systems is a multi-access
technology under the interference limited environment. It can process more number of subscribers compared to other systems
(TDMA system has the processing capacity three times greater than the existing FDMA system whereas CDMA system, about
12~15 times of that of the existing system).
CDMA systemcan be explained as follows: TDMA or SDMA can be used to enable each person to talk alternately or provide a
separate roomfor eachperson when two persons desire to talk with each other at the same time, whereas FDMA can be used to
enable one person to talk in soprano, whereas the other in bass (one of the two talkers can carry out synchronization for hearing
in case there is a bandpass filter function in the area of the hearer).
Another method available is to make two persons to sing in different languages at the same time, space, and frequency when
wishing to let the audience hear the singing without being confused. This is the characteristics of CDMA.
On the other hand, when employing the CDMA technology, each signal has a different pseudo-random binary sequence used to
spread the spectrum of carrier. A great number of CDMA signals share the same frequency spectrum. In the perspective of
frequency area or time area, several CDMA signals are overlapped. Among these types of signals, only desired signal energy is
selected and received through the use of pre-determined binary sequence; desired signals can be separated and then, received
with the correlator used for recovering the spectrum into its original state. At this time, the spectrums of other signals that have
different codes are not recovered into its original state and instead, processed as noise and appears as the self-interference of the
system.
CHAPTER 1. System Introduction

2. Features and Advantages of CDMA Module
2.1 Various Types of Diversities
In the CDMA broadband modulation(1.25MHz band), three types of diversities (time, frequency, and space) are used to reduce
serious fading problems generated from radio channels in order to obtain high-quality calls.
Time diversity can be obtained through the use of code interleaving and error correction code whereas frequency diversity can
be obtained by spreading signal energy to more wider frequency band. The fading related to normal frequency can affect the
normal 200~300kHz among signal bands and accordingly, serious affect can be avoided. Moreover, space diversity (also called
path diversity) can be realized with the following three types of methods.
First, it can be obtained by the duplication of cell site receive antenna. Second, it can be obtained through the use of multi-signal
processing device that receives a transmit signal having each different transmission delay time and then, combines them. Third, it
can be obtained through the multiple cell site connection (Soft Handoff) that connects the mobile station and more than two cell
sites at the same time.
2.2 Power Control
The CDMA system utilizes the forward (from a base station to mobile stations) and backward (from the mobile station to the
base station) power control in order to increase the call processing capacity and obtain high-quality calls. In case the originating
signals of mobile stations are received bythe cell site in the minimumcall qualitylevel (signal to interference) through the use of
transmit power control on all the mobile stations, the systemcapacity can be maximized.
If the signal of mobile station is received too strong, the performance of that mobile station is improved. However, because of
this, the interference on other mobile stations using the same channel is increased and accordingly, the call quality of other
subscribers is reduced unless the maximumaccommodationcapacityis reduced.
In the CDMA system, forward power control, backward open loop power control, and closed loop power control methods are
used. The forward power control is carried out in the cell site to reduce the transmit power on mobile stations less affected by
the multi-path fading and shadow phenomenon and the interference of other cell sites when the mobile station is not engaged in
the call or is relatively nearer to the corresponding cell site. This is also used to provide additional power to mobile stations
having high call error rates, located in bad reception areas or far away from the cell site.
The backward open loop power control is carried out in a corresponding mobile station; the mobile station measures power
received from the cell site and then, reversely increases/decreases transmit power in order to compensate channel changes
caused by the forward link path loss and terrain characteristics in relation to the mobile station in the cell site. By doing so, all
the mobile office transmit signals in the cells are received bythe cell site in the same strength.
Moreover, the backward closed loop power control used by the mobile station to control power with the commands issued out
by the cell site. The cell site receives the signal of each corresponding mobile station and compares this with the pre-set
threshold value and then, issues out power increase/decrease commands to the corresponding mobile station every 1.25 msec
(800 times per second).
By doing so, the gain tolerance and the different radio propagation loss on the forward/backward link are complemented.

2.3 Voice Encoder and Variable Data Speed
The bi-directional voice service having variable data speed provides voice communication which employs voice encoder
algorithm having power variable data rate between the mobile telephone cell site and mobile station. On the other hand, the
transmit voice encoder performs voice sampling and then, creates encoded voice packets to be sent out to the receive voice
encoder, whereas the receive voice encoder demodulates the received voice packets into voice samples.
One of the two voice encoders described in the above is selected for use depending on inputted automatic conditions and
message/data; both of them utilize four-stage frames of 9600, 4800, 2400, and 1200 bits per second. In addition, this type of
variable voice encoder utilizes adaptive threshold values whenselecting required data rate. It is adjusted in accordance with the
size of background noise and the data rate is increased to high rate only when the voice of caller is inputted.
Therefore, background noise is suppressed and high-quality voice transmission is possible under the environment experiencing
serious noise. In addition, in case the caller does not talk, data transmission rate is reduced so that the transmission is carried out
inlow energy. This will reduce the interference on other CDMA signals and as a result, improve system performance (capacity,
increased by about two times).
2.4 Protecting Call Confidentiality
CDMA signals have the function of effectively protecting call confidentiality by spreading and interleaving call information in
broad bandwidth. This makes the unauthorized use of crosstalk, search receiver, and radio very hard substantially. Also included
is the encryption function on various authentication and calls specified in IS-95 for the double protection of call confidentiality.
2.5 Soft Handoff
During the soft hand, the cell site already in the busy state and the cell site to be engaged in the call later participate in the call
conversion. The call conversion is carried out through the original call connection cell site, both cell sites, and then, new cell
site. This method can minimize call disconnection and prevent the user from detecting the hand-off.
2.6 Frequency Re-Use and Sector Segmentation
Unlike the existing analog cellular system, the CDMA system can reuse the same frequency at the adjacent cell and accordingly,
there is no need to prepare a separate frequency plan. Total interference generated on mobile station signals received from the
cell site is the sum of interference generated from other mobile stations in the same cell site and interference generated from the
mobile station of adjacent cell site. That is, each mobile station signal generates interference in relation to the signals of all the
other mobile signals.
Total interference fromall the adjacent cell sites is the ratio of interference from all the cell sites versus total interference from
other mobile stations in the same cell site (about 65%). In the case of directional cell site, one cell normally uses a 120°sector
antenna in order to divide the sector into three. In this case, each antenna is used only for 1/3 of mobile stations in the cell site
and accordingly, interference is reduced by 1/3 on the average and the capacity that can be supported by the entire system is

increased by three times.
2.7 Soft Capacity
The subscriber capacity of CDMA systemis flexible depending on the relation between the number of users and service classes.
For example, the systemoperator can increase the number of channels available for use during the busy hour despite the drop in
call quality. This type of function requires 40% of normal call channels in the standby mode during the handoff support, in an
effort to avoid call disconnection resulting from the lack of channels.
In addition, in the CDMA system, services and service charges are classified further into different classes so that more transmit
power can be allocated to high class service users for easier call set-up; they can also be given higher priority of using hand-off
function than the general users.

3. Structure and Functions of CDMA Module
The mobile station of CDMA system is made up of a radio frequency part and logic/control (digital) part. The mobile station is
fully compatible with the existing analog FM system. The mobile station antenna is connected with the transmitter/receiver via a
duplexer filter so that it can carry out the transmit/receive function at the same time.
The transmit frequency is the 25MHz band of 824~849MHz, whereas the receive frequency is the 25MHz band of 869~894MHz.
The transmit/receive frequency is separated by 45MHz. The RF signal from the antenna is converted into intermediate
frequency(IF) band by the frequency synthesizer and frequency down converter and then, passes the bandpass SAW filter having
the 1.25MHz band. IF output signals that have been filtered fromspurious signal are converted into digital signals via an analog-
to-digital converters(ADC) and then, sent out respectively to 5 correlators in each CDMA de-modulator. Of these, one is called a
searcher whereas the remaining 4 are called data receiver(finger). Digitalized IF signals include a great number of call signals
that have been sent out by the adjacent cells. These signals are detected with pseudo-noise sequence (PN Sequence). Signal to
interference ratio (C/I) on signals that match the desired PN sequence are increased through this type of correlation detection
process. Then, other signals obtain processing gain by not increasing the ratio. The carrier wave of pilot channel from the cell
site most adjacently located is demodulated in order to obtain the sequence of encoded data symbols. During the operation with
one cell site, the searcher searches out multi-paths in accordance with terrain and building reflections. On three data receivers,
the most powerful four paths are allocated for the parallel tracing and receiving. Fading resistance can be improved a great deal
by obtaining the diversity combined output for de-modulation. Moreover, the searcher can be used to determine the most
powerful path from the cell sites even during the soft handoff during the two cell sites. Moreover, four data receivers are
allocated in order to carry out the de-modulation of these paths. Data output that has been demodulated change the data string in
the combined data row as in the case of original signals(deinterleaving), and then, are de-modulated by the forward error
correction decoder which uses the Viterbi algorithm.
On the other hand, mobile station user information sent out from the mobile station to the cell site pass through the digital voice
encoder via a mike. Then, they are encoded and forward errors are corrected through the use of convolution encoder. Then, the
order of code rows is changed in accordance with a certain regulation in order to remove any errors in the interleaver. Symbols
made through the above process are spread after being loaded onto PN carrier waves. At this time, PN sequence is selected by
each address designated in each call.
Signals that have been code spread as above are digital modulated (QPSK) and then, power controlled at the automatic gain
control amplifier (AGC Amp). Then, they are converted into RF band by the frequency synthesizer synchronizing these signals to
proper output frequencies.
Transmit signals obtained pass through the duplexer filter and then, are sent out to the cell site via the antenna.

4. Specification
4.1 General Specification
4.1.1 Transmit/Receive Frequency Interval : 45 MHz
4.1.2 Number of Channels (Channel Bandwidth)
CDMA : 20 CH (BW: 1.23MHz)
41.3 Operating Voltage : DC 6V
4.1.4 Operating Temperature : -30°
°°
°~ +60°
°°
°
4.1.5 Frequency Stability : ±300 Hz
4.1.6 Antenna : Whip antenna, 50 Ω
ΩΩ
Ω
4.1.7 Size and Weight
1) Size : 102mmx 80mmx 36mm(L x Wx D)
2) Weight : About 180g
4.1.8 Channel Spacing : 1.25MHz
4.2 Receive Specification
4.2.1 Frequency Range
Digital : 869.04 MHz ~ 893.97 MHz
4.2.2 Local Oscillating Frequency Range : 966.88MHz±12.5MHz
4.2.3 Intermediate Frequency : 85.38MHz
4.2.4 Sensitivity : -104dBmUnder
4.2.5 Selectivity
CDMA : 3dB C/N Degration (With Fch±1.25 kHz : -30dBm)
4.2.6 Spurious Wave Suppression : Maximum of -80dB
4.2.7 CDMA Input Signal Range
•
••
•Dynamic area of more than-104~ -25dBm: 79dB at the 1.23MHz band.

4.3 Transmit Specification
4.3.1 Frequency Range
824.04 MHz ~ 848.97 MHz
4.3.2 Local Oscillating Frequency Range : 966.88 MHz±12.5 MHz
4.3.3 Intermediate Frequency : 130.38 MHz
4.3.4 Output Power : 0.32W
4.3.5 Interference Rejection
1) Single Tone : -30dBmat 900 kHz
2) Two Tone : -43dBmat 900 kHz & 1700kHz
4.3.7 CDMA TX Frequency Deviation : +300Hz or less
4.3.8 CDMA TX Conducted Spurious Emissions
•
••
•900kHz : - 42 dBc/30kHz below
•
••
•1.98MHz : - 54 dBc/30kHz below
4.3.9 CDMA Minimum TX Power Control : - 50dBm below

4.4 MS (Mobile Station) Transmitter Frequency
FA NO. CH.NO. CENTER FREQUENCY FA NO. CH.NO. CENTER FREQUENCY
1
2
3
4
5
6
7
8
9
10
1011
29
70
111
152
193
234
275
316
363
824.640 MHz
825.870 MHz
827.100 MHz
828.330 MHz
829.560 MHz
830.790 MHz
832.020 MHz
833.250 MHz
834.480 MHz
835.890 MHz
11
12
13
14
15
16
17
18
19
20
404
445
486
527
568
609
650
697
738
779
837.120 MHz
838.350 MHz
839.580 MHz
840.810 MHz
842.04 MHz
843.270 MHz
844.500 MHz
845.910 MHz
847.140 MHz
848.370 MHz
4.5 MS (Mobile Station) Receiver Frequency
FA NO. CH.NO. CENTER FREQUENCY FA NO. CH.NO. CENTER FREQUENCY
1
2
3
4
5
6
7
8
9
10
1011
29
70
111
152
193
234
275
316
363
869.640 MHz
870.870 MHz
872.100 MHz
873.330 MHz
874.560 MHz
875.790 MHz
877.020 MHz
878.250 MHz
879.480 MHz
880.890 MHz
11
12
13
14
15
16
17
18
19
20
404
445
486
527
568
609
650
697
738
779
882.120 MHz
883.350 MHz
884.580 MHz
885.810 MHz
887.04 MHz
888.270 MHz
889.500 MHz
890.910 MHz
892.140 MHz
893.370 MHz

1.INSTALLATION METHOD
CHAPTER 2. NAM Input Method

1) Connect the MODEM to 60pin connector of Level Translator.
2) Supply the voltage of 5~7V to small or large jack of Level Translator.
3) Switch the power on.
4) Connect the UART1 to PC COM1 port with the RS-232C cable.
5) Install the operating program.
2. OPERATION METHOD
2) Set Buad rate to the modem’s.
3) Click [DM mode]
1) Run PSTDM program at Windows95 or Windows98

4) If OK is displayed in the message box, modem is now ready for
ommunication with PC.
5) Click MENU B
A
R icon.

6) As shown in the picture above, service file input plane will be displayed
(See if clock is running. If it isn’t, communication with PC is not
activated.
Repeat step 1 through 5, or reset the power of modem and repeat step 1
through 5)
7) Type NAM Programming script like the example shown below,
<NAM Programming script example>
Mode offline-d [ENTER]
nv_write name_nam {0," AnyDATA telecom "} [ENTER]
nv_write name_nam {1," AnyDATA telecom "} [ENTER]
Mode reset [ENTER]
SCRIPTINPUT WINDOW

1. Overview
IRT3000 receives modulated digital signals from the MSM of the digital circuit and then, changes them into analog
signals by the digital/analog converter (DAC, D/A Converter) in order to create baseband signals. Created baseband
signals are changed into IF signals by IFT3000 and then, fed into the Mixer after going through AGC. IF signals that
have been fed are mixed with the signals of VCO and changed into the RF signals and then, they are amplified at the
Power AMP. Finally, they are sent out to the cell site via the antenna after going through the isolator and duplexer.
2. RF Transmit / Receive Part
2.1 CDMA Transmit End
8 bit I and Q transmit signals are inputted into 2 DACs (DIGITAL-TO-ANALOG CONVERTER) from the output
terminal TX_IQDATA0 ~ TX_IQDATA7 of MSM through the input terminals TXD0~TXD7 of BBA. Transmit
signal input speed is two times of TXCLK+, TXCLK- which are two transmit/receive reference frequency.
Among transmit signals being inputted, signals are inputted into I signal DAC when the transmit clock is in the rise
edge, whereas signals are inputted into Q Signal DAC during the drop edge. I and Q transmit signals are
compensated and outputted at MSM in order to compensate the 1/2 clock time difference generated between
reference clocks. In the signals coming out from the output terminal of DAC, there are spurious frequency
ingredients resulting from DAC output transition edge and parasite ingredients, transmit clock frequencies and
harmonics which are unwanted signals. Accordingly, spurious ingredients are removed by passing the signals
through LPF of passband 6.30KHz. Unlike the receive end, the transmit end LPF requires no OFFSET adjustment.
Analog baseband signals that have passed the CDMA LPF are mixed with I and Q signals of frequency 130.38 MHz
(260.76 MHz created in the BBA internal VCO are divided by half into frequency 130.38MHz having the phase
difference of 90 degrees) in two mixers. The mixed signals are added again and converted into IF frequency 130.38
MHz ±630 KHz (CDMA Spread Power Density Modulated Signals) and then, outputted.
2.2. Tx IF/Baseband Processors, IFT3000 (U105)
The IFT3000 includes digital-to-analog converters(DAC) for converting digital baseband to analog baseband, low-
pass filters, a mixer for up-converting to IF and an 85 dB dynamic range Tx AGC amplifier. The IFT3000 includes
a fully programmable phase-locked loop(PLL) for generating Tx LO and IF frequencies. The IFT3000 also has an 8-
bit general purpose ADC with three selectable inputs for monitoring battery level, RF signal strength and phone
CHAPTER 3. Circuit Description

temperature.
2.3. Upconverter (U104)
Upconverters made up of a mixer part and Driver AMP part. The mixer part is used to receive
double-balanced OUT+ and OUT- of transmit AGC from baseband and mix the output of VCO (U171) with UHF
output signal, whereas the Amp part is used to buffer the output of this mixer. U105 has the operation range of
RF500MHz~1500MHz and has the conversion gain of 0 dB. In addition, the suppression of spurious signals which
are unwanted noise is about 30 dBc when being compared to RF output. The IF input signal range of the mixer is
DC~200MHz. The isolation on RF output terminal and LO signal input terminal at the IF input terminal is 30dB.
The range of LO signal that can be inputted is 300~1700MHz and power level is -6~0 dBm.
2.4. Transmit Bandpass Filter (F102, F103)
Transmit signals that have been converted from IF signals into RF signals after passing through the upconverter
U105 are inputted into the Power Amp U102 after passing once again through RF BPF F102 in order to filter out
noise signals amplified during the amplification of RF signals after going through upconverter(U105). This is carried
out in order to create power level inputted to the Power AMP via RF BPF F102. IL of two RF BPFs is 4dB as a
maximum, whereas the ripple in the passing band is 2dB(maximum). The degree of the suppression of transmit
signals on receive band is at least 20dB or greater. The maximum power that can be inputted is about 25dBm.
2.5. Power Amplifier (U102)
The power amplifier U102 that can be used in the CDMA and FM mode has linear amplification capability,
whereas in the FM mode, it has a high efficiency. For higher efficiency, it is made up of one MMIC (Monolithic
Microwave Integrated Circuit) for which RF input terminal and internal interface circuit are integrated onto one IC
after going through the AlGaAs/GaAs HBT (heterojunction bipolar transistor) process. The module of power
amplifier is made up of an output end interface circuit including this MMIC. The maximum power that can be
inputted through the input terminal is +17dBm and conversion gain is about 28dB. RF transmit signals that have
been amplified through the power amplifier are sent to the duplexer and then, sent out to the cell site through the
antenna in order to prevent any damages on circuits, that may be generated by output signals reflected from the
duplexer and re-inputted to the power amplifier output end.

2.6. Description of Frequency Synthesizer Circuit
2.6.1 Voltage Control Temperature Compensation Crystal Oscillator(U174, VCTCXO)
The temperature range that can be compensated by U174 which is the reference frequency generator of mobile
terminal is -30 ~ +80 degrees. U174 receives frequency tuning signals called TRK_LO_ADJ from MSM as
0.5V~2.5V DC via R and C filters in order to generate the reference frequency of 19.68MHz and input it into the
frequency synthesizer of UHF band. Frequency stability depending on temperature is ±2.0 ppm.
2.6.2 UHF Band Frequency Synthesizer (U172)
Reference frequency that can be inputted to U172 is 3MHz~40MHz. It is the dual mode
frequency synthesizer (PLL) that can synthesize the frequencies of UHF band 50MHz~1200MHz and IF band
20MHz~300MHz. U172 that receives the reference frequency of 19.68MHz from U174 creates 30kHz comparison
frequency with the use of internal program and then, changes the frequency of 900MHz band inputted from X200
which is the voltage adjustment crystal oscillator into the comparison frequency of 30kHz at the prescaler in U172.
Then, two signal differences are calculated from the internal phase comparator. The calculated difference is
inputted to DC for adjusting the frequency of U174 through U172 No.2 PIN and external loop filter in order to
generate UHF signals. In addition, outputs of other PIN17 are inputted into BBA after going through the VRACTOR
diode and tank circuit so that the outputs of BBA internal receive end VCO are adjusted to 170.76MHz.
2.6.3 Voltage Control Crystal Oscillator (U171)
U171 that generates the LO frequency (900MHz) of mobile terminal receives the output voltage of PLL U172 and
then, generates the frequency of 954MHz at 0.7V and the frequency of 980MHz at 2.7V. The sensitivity on control
voltage is 23MHz/v and the output level is 1dBm(maximum). Since LO frequency signal is very important for the
sensitivity of mobile terminal, they must have good spurious characteristics. U174 is -70dBc(maximum).
3. Digital/Voice Processing Part
3.1 Overview
The digital/voice processing part processes the user's commands and processes all the digital and voice signal
processing in order to operate in the phone. The digital/voice processing part is made up of a receptacle part, voice
processing part, mobile station modem part, memory part, and power supply part.