Inovonics 540 Manual

OPERATING AND MAINTENANCE
INSTRUCTION MANUAL
MODEL 540
FM SUBCARRIER MONITOR/DEMOD
__________
interstage
Phistersvej 31, 2900 Hellerup, Danmark
Telefon [phone], fax [phone]
www.interstage.dk
-pro audio with a smile

—–USER’S RECORD —–
Model 540 -Serial No. _______
Date Purchased _____________
Warranty Card Mailed —¨
OPERATING AND MAINTENANCE
INSTRUCTION MANUAL
MODEL 540
RDS/RBDS RADIODATA ENCODER
January, 1998
(Effective with Serial No. 026)
1305 Fair Avenue •Santa Cruz, CA 95060
TEL: [phone] • FAX: [phone]
Visit our Website: www.inovon.com

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TABLE OF CONTENTS
Section I -INTRODUCTION
Model 540 Product Description ...............................................................................................3
General -FCC Type Acceptance -Features
Model 540 Technical Specifications........................................................................................4
Block Diagram ...........................................................................................................................5
Section II -INSTALLATION
Unpacking and Inspection .......................................................................................................6
Mounting ....................................................................................................................................6
Rack Requirements -Heat Dissipation
AC (Mains) Power .....................................................................................................................6
As Delivered -Voltage Selector -Power Cord
Radio Frequency Interference (RFI) .....................................................................................7
Location -Ground Loops
Jumpering Options) ..................................................................................................................7
Section III -SETUP AND OPERATION
Panel Controls and Indicators .................................................................................................9
Meter Select -Subcarrier Tuning -Filter -SCA Audio -
Phones -Power
MPX Input and Level Set ........................................................................................................10
Input Connection -Correcting for Response Errors -Input Level
Adjustment
Section IV -RDS-DECODE OPTION
Installing the Optional Plug-in RDS Card ............................................................................12
Computer Requirements .......................................................................................................12
Installing the Software ...........................................................................................................13
DOS-Based Computers -Computers Running Windows®
Running the DETECT Program ..............................................................................................13

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Starting the Program Under DOS -Running Under Windows®-
The DETECT Screen -Data Error Display
Section V -CIRCUIT DESCRIPTIONS
Introduction .............................................................................................................................15
Navigating the Schematics -The “PIC” and Front-Panel Logic
Input Conditioning and First Two Conversions ..................................................................15
Input Stage and Band-Pass Filter -Programmable First LO -
First IF and Second LO
Second IF and SCA Demodulation .......................................................................................16
Second IF Filter -SCA Demodulator -De-Emphasis, Audio
Output and Monitoring
Third(!) Conversion ................................................................................................................17
LO and Mixer -IF Filtering
Metering ...................................................................................................................................17
Metering Selector -Meter Rectifier -Bargraph Display
RDS Option Plug-In Assembly ..............................................................................................18
Baud Rate Jumper
Power Supply ...........................................................................................................................18
Model 540 Calibration Procedures .......................................................................................19
R14: Input Gain and Flatness Check -R19 and R64: Injection
and Data Level Set -R20: SCA Deviation -R21: SCA Audio
Level Set
Section VI -APPENDIX
Parts Lists -Schematics -Warranty .................................................................................21

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Section I
INTRODUCTION
MODEL 540 PRODUCT DESCRIPTION
GeneralInovonics’ Model 540 enables accurate measurement and monitoring of
FM broadcast subcarriers. These may include speech and music “SCA”
(Subsidiary Carrier Authorization) transmissions, “RDS” (Radio Data
System) information, and various existing-and-proposed “high-speed”
digital services which provide paging and other one-way data
communications.
The 540 accepts the demodulated FM “baseband” signal feed from any
Modulation Monitor. It is frequency-agile, tuning any subcarrier
frequency between 54kHz and 99kHz with digital precision. Bargraph
metering displays subcarrier injection, as well as subcarrier deviation
for SCA audio transmissions. Demodulated SCA audio may be
monitored with headphones and is available at a rear-panel connector
as well.
FCC Type
Acceptance Equipment for monitoring broadcast transmissions in the U.S. no longer requires “type acceptance” by the Federal Communications
Commission. Though rules pertaining to monitoring equipment have
been relaxed or abandoned, the broadcaster remains responsible in
ensuring that his transmitted signal conforms to current FCC
regulations.
Features Features of the Inovonics 540 include:
•Works with any FM Mod-Monitor having a composite-
baseband (MPX) output. Easily calibrated with built-
in CAL facility.
•Measures injection level of SCA, RDS and high-speed
data subcarriers.
•Demodulates audio SCAs and accurately displays
subcarrier deviation.
•Triple-conversion design with precise, crystal-
controlled digital tuning. Dual IF bandwidth gives
optimum selectivity.
•An optional RDS data decoder module is available, and
is supplied with comprehensive radio-data analysis
software.

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MODEL 540 TECHNICAL SPECIFICATIONS
Subcarrier Tuning Range:
54kHz to 99kHz in 1kHz
increments.
Subcarrier Injection
Measurement:
a:±1kHz to ±10kHz of main
carrier deviation with ±250Hz
resolution.
b: 1% to 13% of main carrier
modulation with 1/3% reso-
lution (100% modulation
equivalent to ±75kHz
deviation).
Measurement Bandwidth:
WIDE: 12kHz filter for SCA and
certain high-speed data
channels.
NARROW: 3.5kHz filter for RDS
and similar narrowband data
channels.
SCA Deviation Measurement:
Absolute: ±1kHz to ±10kHz
audio subcarrier deviation
with ±250Hz resolution
Relative: dB scale indicates
–20dB to +2.5dB. “0dB” is
factory-set to ±5kHz devia-
tion; may be recalibrated by
user.
Calibration Provision:
Total, main-channel carrier
deviation is monitored in the
CALIBRATE mode and adjusted to
reflect the station’s primary
Modulaton Monitor readings.
Metering:
The 38-segment bargraph display
is peak-responding and
incorporates a peak-hold feature.
SCA Audio Response:
±0.5dB, 50Hz to 5kHz. Switch
selection of FLAT or 150-micro-
second DE-EMPH(asis).
SCA Distortion and Noise:
Better than 40dB, unweighted,
below ±5kHz deviation.
Audio Outputs:
a: Rear-panel, active-balanced
SCA program output.
b: Front-panel headphone jack
monitors SCA audio, switches
to main channel (mono) in
CALIBRATE mode.
Composite (MPX) Input:
Unbalanced, bridging; requires
1V p-p or greater signal equivalent
to ±75kHz main channel
deviation.
RDS Decoder Option:
A plug-in module formats raw RDS
data to RS-232. Supplied software
enables detailed RDS data analysis
with any IBM-compatible PC.
Power Requirements:
105–130VAC or 210–255VAC,
50/60Hz; 15 watts.
Size and Weight:
1¾”H x 19”W x 7”D (1U);
7 lbs. (shipping).

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BLOCK DIAGRAM
A simplified Block Diagram of the Model 540 is shown in Figure 1,
below. Monitor circuitry is detailed in the Circuit Descriptions section
beginning on Page 15. These descriptions reference Schematic
Diagrams found in the Appendix.
Figure 1 -Block Diagram, Model 540 FM Subcarrier Monitor/Demod
MPX
INPUT 50kHz-100kHz
BANDPASS
INPUT
GAIN FIRST MIXER
455kHz
BAND-PASS
SECOND MIXER
25kHz
BAND-PASS
SYNTHESIZER
CONTROLLER SYN. LO
67
SUB.
TUNING
480kHz
LO
DOUBLING
MONOSTABLE 5kHz LOW-PASS SCA DE-EMPHASIS
25kHz
LO
3kHz
LOW-PASS M
E
T
E
R
I
N
G
S
E
L
E
C
T
O
R
METER
RECT. METER INTEG.
MAIN CHAN.
DE-EMPHASIS
BALANCED
SCA AUDIO
PHONES
DE-EMPH
FLAT
SCA
THIRD
MIXER
FILTER
WIDE
NAR-
ROW
BALANCING AMP
HEADPHON
E
FM DEMOD LIMITING
BARGRAPH

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Section II
INSTALLATION
UNPACKING AND INSPECTION
Immediately upon receipt of the equipment, inspect carefully for any
shipping damage. If damage is suspected, notify the carrier at once, then
contact Inovonics.
It is recommended that the original shipping carton and packing
materials be set aside for future reshipment. In the event of return for
Warranty repair, shipping damage sustained as a result of improper
packing for returnmay invalidate the Warranty!
IT IS VERY IMPORTANT that the Warranty Registration
Card found at the front of this Manual be completed and
returned. Not only does this assure coverage of the equip-
ment under terms of the Warranty, and provide some means
of trace in the case of lost or stolen gear, but the user will
automatically receive specific SERVICE OR MODIFICA-TION
INSTRUCTIONS should they be issued by Inovonics.
MOUNTING
Rack
Requirement The Model 540 Monitor mounts in a standard 19-inch equipment rack and requires only 1¾ inches (1U) of vertical rack space. Plastic
“finishing” washers will protect the painted finish around the
mounting holes.
Heat
Dissipation Consuming about the same power as a single string of Christmas “twinkle” bulbs, the 540, itself, generates negligible heat. The unit is
specified for operation within an ambient temperature range extending
from freezing to 120°F/50°C. Because adjacent, less efficient
equipment may radiate substantial heat, be sure that the equipment
rack has sufficient ventilation to keep internal temperature below the
specified maximum.
AC (MAINS) POWER
As delivered
Unless specifically ordered for export shipment, the Model 540 is set at
the factory for operation from 115V, 50/60Hz AC mains. The rear-panel
designation next to the fuseholder will confirm both the mains voltage

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designation next to the fuseholder will confirm both the mains voltage
selected and the value of a proper fuse.
Voltage
Selector A mains voltage selector switch is located beneath the top cover of the unit, close to the AC mains connector on the circuit board. With
primary AC power disconnected,you may slide the red actuator with a
small screwdriver so that the proper mains voltage designation (115 or
230) shows. Be certain always to install an appropriate fuse, and check
that the rear-panel voltage/fuse designation is properly marked. It is
factory practice to cross-out the inappropriate designation with an
indelible black marking pen. You can remove this strikethrough with
lacquer thinner or a similar, probably carcinogous solvent to
redesignate.
BE SURE that the mains voltage selector setting and pri-
mary fuse value are appropriate for the mains supply before
plugging the 540 Monitor into the wall outlet.
Power Cord The detachable IEC-type power cord supplied with the Monitor is fitted
with a North-American-standard male plug. Nevertheless, the
individual cord conductors aresupposed to be color-coded in accordance
with CEE standards; that is:
BROWN = AC “HOT” BLUE = AC NEUTRAL GRN/YEL = GROUND
If this turns out not to be the case, we offer our apologies (cord vendors
sometimes lie to us) and advise that US color coding applies:
BLACK = AC “HOT” WHITE = AC NEUTRAL GREEN = GROUND
RADIO FREQUENCY INTERFERENCE ( R F I )
Location Although we have anticipated 540 installation in a broadcast
environment, you should practice care in locating the unit away from
abnormally high RF fields.
Ground Loops Because the input and the output of the Model 540 are chassis-ground-
referenced, a mains frequency or RF ground loop could be formed
between the input or output cable shield grounds and the AC power
cord ground. A “ground-lifting” AC adapter will probably remedy any
problem, though the chassis somehow must be returned to earth
ground for safety. Generally, being screwed-down in the equipment
rack will satisfy the safety requirement.
JUMPERING OPTIONS
The Model 540 has but a single jumpering option. It selects either 50µs
or 75µs de-emphasis for the monaural, main-channel program audio

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which is routed to the front-panel PHONES jack in theCALIBRATION
mode.
The de-emphasis jumper strip is located to the left of IC28. The circuit
board legend identifies the “50” and “75” (microsecond) positions for
the movable jumpering shunt; this jumper will have been positioned
appropriately for the original shipping destination.