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High speed digital systems laboratoryהמעבדה למערכות ספרתיות מהירות

הטכניון - מכון טכנולוגי לישראל

הפקולטה להנדסת חשמל

Technion - Israel institute of technologydepartment of Electrical Engineering

Midterm Presentation

Performed by: Carmel Yuval, Mishael Avihoo

Instructor: Orbach Mony

Cooperated with: Qualcomm Israel

Transfer fax over IP in cellular networks


Project Goal

Transmit fax page from a fax machine to

a computer and receive a fax page from a

computer to a fax machine.


Block Diagram

FaxFax ComputerComputerSLICSLIC

Control/Control/feedbackfeedback

DSPDSP


Functional Description• Converting analog fax transmission to a digital signal

• Decoding and interpreting the digital signal

• Determine the fax call state from the digital signal using state

machine, negotiating accordingly with the computer

• Transmitting an image information to the computer using

AT-Commands

• Repeating the process for the case of the computer initiating

the fax call


Interfaces

CONTROLPC

PCEMULATE

IWF

PCM

PCM

EZ

-ICE

EZ

-KIT

RS-232

EvaluatingBoard

Parallel Interface

ADSP-2181

SCLK0

DT0

DR0

RFS0

DT1

DR1ProSLIC

PCLK

DRX

DTX

FSYNCSCL

K

CS

SDI

SD

O

LOCALFAX A

nalo

g


Interfaces (cont.)

• ProSLIC

• Parallel port – to controller (computer).

• Analog – to phone line (200-2200Hz).

• Serial – PCM digital signal to DSP (2.048MHz).

• DSP

• Serial RS-232 – to PC emulating IWF (4800-19200bps).

• EZ-ICE – for debugging DSP (9600bps).

• Serial – PCM digital signal to ProSLIC (2.048MHz).


Data Rates and Bandwidths

Place Rate / Frequency

Input (Phone Line) 200-2200Hz

Output (RS-232) 4800 - 19200bps

PCM interface 2.048MHz

DSP clock 20MHz

PCM Sampling Rate 8KHz


Built In Tests• Program debugging

• Using VisualDSP+EZ-ICE.

• Log points – TBD.

•ProSLIC

• Power on – Power LEDs.

• Computer interface – Using program.

• Phone line interface – Tone generation, using fax.

• PCM interface – TBD.


Built In Tests (cont.)

• DSP

• Power on – Power LEDs.

• Computer interface – TBD.

• PCM interface - TBD.

• EZ-ICE interface – TBD.


Complete System Overview

IWF MSC BSC

BTS

PSTN

MSDSPHOST

FAX

FAXWireless


Complete System Overview (cont.)

• MS – Mobile Station - Wireless communication device,

contains the DSP, interfaces the fax to the cellular network.

• BTS – Base Transceiver Station – Connects the MS to the

cellular network using wireless interface.

• BSC – Base Station Controller – Controls Resources.


Complete System Overview (cont.)

• MSC – Mobile Switching Center – The cellular network

PSTN.

• IWF – Inter Working Function – Connects the cellular

network to PSTN using modems (Dial up, fax, etc.).

• PSTN – Public Switching Telephone Network – connects

subscribers.


Project’s Alternatives

• External Modem – Of the shelf solution, cheap, but large, can

not generate PSTN functions.

• Canceling Vocoder (voice compression algorithm) – Not

supported.


ProSLIC• Provides a complete analog telephone interface.

• “Subscriber Line Interface Circuit”.

• codec.

• DTMF functions.

• Signal generation functions (linefeed).

• Consist A/D, D/A, DC to DC converter, programmable signal

generator, signal detector and much more on one chip.


ProSLIC (cont.)

• codec (coder decoder):

• Convert analog signal to PCM.

• Convert PCM to analog signal.

• Comply with A-Law, μ-Law.


ProSLIC (cont.)

• DTMF functions:

• “Dual Tone Multi Frequency”.

• Two frequency generators for generating DTMF signals.

• DTMF detection.


ProSLIC (cont.)

• Linefeed:

• on-hook voltage.

• off-hook loop current.

• on-hook transmission ringing voltage.


DSP Software

• The project consist of written program which works with a

host processor.

• The written software will be alternated in order to disable the

host interface.


DSP Software (cont.)

DSP

DPR(SM)

HOSTIWFInterrupts



• The host and the DSP shares RAM for exchange commands

and data.

• When the host or the DSP puts new data at the shared

memory, they initiates interrupt to inform the other side about

the new data.



DPR(SM)

PC

DSP

HostModule

Interrupts



DPR(SM)

PC

DSP

HostModule

Interrupts

• The host module is a software function in the DSP.

• The host module will connect the DSP to the PC (IWF) via

RS-232 (SPORT1).

• The module will acts as the host when reading and writing

into the shared memory.

• The module will initiate interrupts to the DSP and respond to

such.


Timetable

Week Duty (Avihoo) Duty (Yuval)

28/12 – 1/1 DSP Integration

(Software)

EZ-ICE Setup

4-8/1 Old Program Integration

Hardware Integration

11-15/1 Writing Module PC Interface

18-22/1 Writing Module ProSLIC issues

25-29/1 Writing Module Interrupt handling

Documents

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