Diagram 1: Block Diagram of ISG3300 Eval Board.
Note:
1. The I2C board is not included. It may be ordered from
Broadcom.
INTRODUCTION
The ISG3300 EVAL Board is a fully implemented
physical layer circuit board used for cable modem
applications. It contains the ISG3300 cable trans-
ceiver, connectors to evaluate the RF characteristics
of the transceiver, modulator and demodulator chips,
ESD protection on the supply lines, and requires one
dual power supply.
CONNECTIONS
The supply voltages required are 5 and 24 Volts DC.
Apply 5 V with Digital Ground to the Power Header
(see Diagram 2a). Apply 24 V with Analog Ground
to the next pins. Each supply’s negative terminal
(analog and digital ground) should be connected to-
gether at the power supply and not on the board.
The parallel port on PC1 connects to the dB 25 con-
nector (refer to Diagrams 1 & 3). Lastly, the I2C
interface board connects to PC2’s parallel port and
its I2C socket connects to the I2C header on the
ISG3300 EVAL Board (refer to Diagram 3 or 4). In
cases where the ISG3300 EVAL Board has a 18X1
connector (see Diagram 2a), the user is advised to
plug the ISG3300 into the header before turning on
the power supplies. Note that pins 1 and 18 are filled
and keyed to minimize misalignments.
ISG3300 Transceiver
RF Input/Output
TxEn
Tx_AGC
Tx+
Tx-
Modulator Demodulator
I2CI2C
Tx F-Connector
Rx F-Connector
CLK
LD_EN
DATA
Parallel Connector
IF+
IF-
RF_AGC
IF_AGC
ISG-AN-01
ISG3300 EVAL BOARD USER GUIDE
MANUAL Version 1.05
05/15/2000
APPLICATION NOTE
Diagram 2a: Top side of EVAL Board.
Diagram 2b: Underside of EVAL Board.
Diagram 3: Test Setup for Transmitter Evaluation
Modulator:
The Broadcom BCM3037 I2C lines are connected
at the bottom left 4-pin Tx header (see Diagram
2). This chip feeds a modulated QPSK/16-QAM
signal and TX_AGC into the ISG3300. Apply 5
volts at the “5 V for Modulator” post (see diagram
2a) before running the software.
Demodulator:
The bottom right 4-pin RX header (see Diagram
2) provides I2C lines to the BCM3116. This chip
controls the two AGC lines on the receiver and
demodulates recovered 5.75 MHz at QAM-64 or
QAM-256 signals. Apply 5 volts at the “5 V for
Demodulator” post (see diagram 2a) before run-
ning the software.
Diagram 4: Test Setup for Receiver Evaluation
Bypassing Mod/Demod Chips
To observe the RF characteristics of the ISG3300
EVAL Board, a few modifications are required. Re-
fer to Diagrams 2a and 2b for locations.
Applying external Tx Frequency
1. Remove R54 and R55.
2. Place R54B and R55B with 0-Ohm resistors.
3. Feed signal into Tx_In F-Connector.
Applying external TX_AGC
1. Remove R29.
2. Apply desired voltage at Tx _AGC (do not
exceed 3.3 volts).
3. Remove R13.
4. Apply 3.3 volts at Tx_EN to turn on the TX
circuitry.
* Eval board to be powered on before starting modulator software.
* Eval board to be powered on before starting modulator software.
ISG3300 EVAL BOARD
PC1 w/ISG2K
software
Spectrum
Analyzer
+58 to +8 dBmV
QAM output
5 V
24 V
Power
Supplies
1 C Interface
Board
2
PC2 w/
Modulator
software
PC1 w/ISG2K
software
ISG3300 EVAL BOARD
Upconverter
+15 to -15 dBmV
QAM input
5 V
24 V
Power
Supplies
1 C Interface
Board
2
PC2 w/
Demodulator
software
QAM generator
PC1 w/ISG2K
software
Modifications to QAM Signal
At the Main Menu, hit F3: Transmit Control
bit-error-rate (BER), SNR statistics on the right.
3. On occasions, jumping into the constellation
screen causes the 3116 to loose track of the
QAM. Press F9: Require to recover the signal.
To change to QAM 256 or Symbol Rate:
1. Hit F3: Select Acq Script.
2. Find the “256” Script.
3. Enter “1” for # of Attempts.
4. Enter “1000” for Wait Time.
5. Press <Enter> a few times to return to the Main
Menu.
6. Hit F4: Set Symbol Rate.
7. Enter the symbol rate as displayed on QAM
Generator.
The following steps will get the user started to gen-
erate a QAM signal.
1. Run the BCM3037.exe executable program.
2. Upon initialization, the main menu for the
UPSTRM Controller will appear. (If “Failed to
Communicate w/ BCM3037” appears, check that
header is connected correctly or check that X1
crystal is operating).
3. The lower right-hand corner gives status of
connection to BCM3037. It should read
I2C_COM_OK (I2C_NOACK indicates bro-
ken connection).
4. Hit F1: Run Command file
5. A list of files will appear.
6. Select QPSK and hit <ENTER>.
7. The main menu screen re-appears. The right
hand side shows the 3037 should be transmit-
ting a 2.56MHz symbol rate, QPSK signal,
centered at 15MHz.
BROADCOM SOFTWARE
Whether the ISG3300 EVAL BOARD is modu-
lating or demodulating data, both cases require
the board to be powered ON before starting the
Broadcom programs. For further detail regarding
the Broadcom software, refer to their Technical
Information for BCM93160/BCM93037.
BCM93037.exe
The program will send commands to the 3037 to
generate the desired QAM output for the return path.
The software also allows the user to modify such
parameters as Tx Freq, symbol rate, and power out-
put (from the chip and from the ISG3300 transmit-
ter).
Applying External Rx AGCs
1. Remove R27 and R74.
3. Apply desired voltage to IF_AGC (do
not exceed 3.3 volts).
4. Apply desired voltage to RF_AGC (do
not exceed 3.3 volts).
Viewing Recovered 5.75 MHz IF_output.
1. Remove R51 and R53 (see Diagram 2b,
underside).
2. Apply R50 and R52 with 0-Ohm resistors.
3. Connector Rx_Out F-connector to spectrum
analyzer to view output.
Screen to give the transmitter status. It is the screen
that allows the user to modify parameters like fre-
quency, symbol rate, amplitude level from the modu-
lator (int power level), and TX_AGC (ext power
level).
BCM93160.exe (or BCM93180.exe)
This program sends commands to the BCM3116
(BCM3118) demodulator chip to recover QAM64
or QAM256 data. It has options to observe charac-
teristics such as constellations, S/N ratio, and pre/
post BER. The program is set up to receive QAM64
with 5 MHz symbol rate, and Digicipher II™ FEC
mode (BCM93180.exe needs DVB FEC mode).
The following steps will get the user started in re-
covering a QAM64 signal:
1. Run the BCM93160.exe (BCM93180.exe) ex-
ecutable program.
2. The main menu for QAMLink Controller will
appear.
3. It should show Error Stat: NO ERROR to con-
firm the connection is good to the BCM3116.
(I2C_NOACK will appear if there are prob-
lems).
4. If communication is good, but the QAM is: Out
of Lock, then hit F1: Reacquire QAM Channel.
The QAM is: In Lock will appear if data is re-
covered.
5. Depending on input RF levels, the SNR Est: is
typically 30 to 36 dB.
To view constellation, follow the following steps:
1. Hit F8: Monitor Constellation.
2. The screen shows a constellation on the left and
Diagram 5: Recommended Pad Layout
ISG SOFTWARE (Channel Selection)
ISG has a software interface program, ISG2000
Demonstration Program, that will program both nec-
essary VCOs frequencies on the ISG3300 to recover
the desired input channel.
1. Run the ISG2K_12B.exe executable program.
2. A Windows-based user interface will appear.
3. Select the desire receiver channel in the R.F.
Freq. box. If the frequency is not there, select a
smaller Step Size, and select Increment or
Decrement.
4. Press Reload to send commands to ISG3300.
After the initial Reload, selecting Increment or
Decrement (in units selected in Step Size box)
will change the LOs to receive the next chan-
nels.
ISG BROADBAND, Inc.
4701 Patrick Henry Drive • SUITE #701 • Santa Clara, CA 95054-1863 • (408) 330-6660
FAX (408) 330-6688 • www.isgbroadband.com
DATA SUBJECT TO CHANGE WITHOUT NOTICE 05/15/2000
