Pira P275 User manual

P275
FM Broadcast Analyzer
User Manual
Firmware version 2.2b
Hardware version 10.2016
Web: http://www.pira.cz E-mail: m[email protected]

2
Table of Contents
Related Documents...........................................................................................................................................................2
Introduction ......................................................................................................................................................................3
Main highlights...................................................................................................................................................................................3
Measurements, indications and outputs...............................................................................................................................................3
Electromagnetic compatibility ............................................................................................................................................................4
Technical Specifications...................................................................................................................................................5
General................................................................................................................................................................................................5
Antenna (RF) Input.............................................................................................................................................................................5
Measurements .....................................................................................................................................................................................6
MPX Input ..........................................................................................................................................................................................6
Alarm Outputs.....................................................................................................................................................................................6
Headphones audio output....................................................................................................................................................................7
Internal RDS/RBDS Decoder..............................................................................................................................................................7
Side connectors and controls...............................................................................................................................................................8
Power supply.......................................................................................................................................................................................9
Mainboard composition ....................................................................................................................................................................10
Alarm outputs....................................................................................................................................................................................12
Operating Instructions ...................................................................................................................................................13
Power-up...........................................................................................................................................................................................13
Control buttons..................................................................................................................................................................................13
Menu.................................................................................................................................................................................................13
RF Measurements...........................................................................................................................................................16
Signal quality ....................................................................................................................................................................................16
Overall frequency deviation (peak frequency deviation)...................................................................................................................19
Pilot deviation...................................................................................................................................................................................19
RDS deviation...................................................................................................................................................................................19
Pilot-to-RDS phase difference...........................................................................................................................................................20
Modulation power (MPX power, Pm)................................................................................................................................................20
Frequency deviation histogram.........................................................................................................................................................21
Service details...................................................................................................................................................................................22
Simple stereo balance meter..............................................................................................................................................................22
Carrier frequency offset ....................................................................................................................................................................23
Radio Data System decoding ............................................................................................................................................................24
USB and COM Port Communication ...........................................................................................................................28
Connecting the FM analyzer to a PC.................................................................................................................................................28
Communication speed selection (autobaud feature)..........................................................................................................................28
List of commands and configuration registers...................................................................................................................................29
Data format .......................................................................................................................................................................................33
Other Features................................................................................................................................................................35
Firmware update ...............................................................................................................................................................................35
Precise carrier frequency offset measurement...................................................................................................................................35
Annexes............................................................................................................................................................................36
Memory map.....................................................................................................................................................................................36
Mainboard mechanical drawing........................................................................................................................................................37
Control interface (J3) connection example........................................................................................................................................38
Related Documents
Visit the Website for the latest documentation version and the following additional documentation:
FM Scope - User Guide (http://pira.cz/fm_broadcast_analyzer/fmscope.pdf)
RDS Spy - RDS Decoder for Windows (http://rdsspy.com/download/mainapp/rdsspy.pdf)

3
Introduction
The P275 FM Broadcast Analyzer is a stand-alone low-cost solution for FM broadcast analysis. It
provides complete FM modulation and basic AF spectrum measurements in FM radio band through the
combined antenna and MPX input.
Built-in LCD display and control interface allows to measure and collect data in terrain without need of
any PC computer. Serial interface and the control software provide a possibility of remote control, data
viewing and automated data logging.
This kind of analyzer is essential equipment for all FM radio stations to ensure compliance with basic
technical broadcast standards and to accomplish the highest audio quality possible.
Main highlights
Stand-alone design, completely DSP based from IF to outputs
Compliant with CEPT/ERC REC 54-01 E and ITU-R SM.1268
Dual-conversion receiver
Built-in LCD display and RS-232 interface
Built-in USB interface
Firmware updates are free
Easy to use
Measurements, indications and outputs
Overall frequency deviation incl. histogram
Modulation power (MPX power)
Baseband spectrum, RF carrier spectrum
Pilot deviation, RDS deviation
Pilot-to-RDS phase difference
FM carrier frequency offset
Reception quality and signal strength
Stereo balance meter
MPX peak to peak voltage
Headphones audio output
Alarm logic or general purpose outputs
RDS/RBDS decoder
Please read this entire manual and familiarize yourself with the controls before attempting to use this equipment.
The equipment has been thoroughly tested and found to be in proper operating condition when shipped. The
manufacturer is not liable for any damages, including but not limited to, lost profits, lost savings, or other incidental or
consequential damages arising out of the use of this product.
No part of this manual may be reproduced or transmitted in any form or by any means, electronic or mechanical,
including photocopying, recording or information storage and retrieval systems, for any purpose other than the
purchaser's personal use.
It is our intention to provide you with the best documentation possible to ensure successful use of the product. If you
wish to provide your comments on organization, clarity, subject matter and ways in which our documentation can better
serve you, please mail us your comments.
Information in this document is subject to change without notice.
Revision: 2018-05-12
Copyright © 1999-2018 PlRA DigitaI s.r.o.

4
Electromagnetic compatibility
The manufacturer declares that the product complies with the essential requirements of applicable European
Directives and carries the CE marking accordingly and in conformity with the following product standards:
EMC Standard
Test conditions
Notes
EN 55011:2009
Class B
In line with EN 61326-1:2013:
EN 61000-3-2:2014
1)
EN 61000-3-3:2013
1)
EN 61000-4-2:2009
Contact discharge ±4 kV
Air discharge ±8 kV
EN 61000-4-3:2006
3 V/m (80 MHz - 1 GHz)
3 V/m (1.4 GHz - 2 GHz)
1 V/m (2 GHz - 2.7 GHz)
EN 61000-4-4:2012
L, N conductors ±1 kV
Capacitive way (antenna cable) ±1 kV
1)
EN 61000-4-5:2006
L, N conductors ±0.5 kV
1)
EN 61000-4-6:2009
3 V, 150 kHz - 80 MHz
EN 61000-4-11:2004
0% UT during half cycle
0% UT during full cycle
70% UT during 25 cycles
short interruption: 0% UT during 250 cycles
1)
Test report no.: 414103294AE1
Issued by: Testing laboratory no. 1004.3, ITC, a.s., CZ
Date: 2016-10-25
Notes:
1) With standard power supply.

5
Technical Specifications
Parameter
Condition
Value
General
Supply voltage
USB, J2
5.0 V DC ±10 %
battery
2.3 –4.3 V DC (2x or 3x AA NiMH)
internal (J17)
5.0 V DC ±5 %
Supply current
LCD off
80 mA
LCD on
140 mA
battery
Up to 280 mA @ 2.4 V
External power supply connectors
USB Micro, pin header
Mainboard dimensions
115 x 65 mm
CPU
70 MIPS DSP
Data connector
RS-232 (DCE, 9 pins), bidirectional,
USB (FTDI based, virtual serial port)
Communication speed
19200 or 115200 bps (autodetect)
Communication mode
1 stop bit, 8 data bits, no parity, (no flow control)
RX buffer length
40 bytes
Signal input
BNC type,
combined antenna (RF) and MPX input with
internal switch.
Antenna (RF) Input
Recommended source impedance
50 Ω
Frequency range
guaranteed
76.0 –108.0 MHz
extended
64.0 –108.0 MHz
Tuning step
selectable 50 kHz or 100 kHz
Input sensitivity
S/N 26 dB
4 μV
basic measurements
30 μV
full measurements
70 μV
Maximum input level
1000 mV (20 mW)
Intermodulation immunity
basic (single input LC circuit with coil tap)
Intermediate frequency (IF)
1st IF
10.7 MHz
2nd IF
0.325 MHz ± 0.005 MHz
Image rejection
+ 21.4 MHz
23 dB
IF bandwidth
280 kHz
Never connect RF power output from the transmitter directly to the device's antenna input!

6
Measurements
Frequency deviation range
min.
0 –121 kHz
Frequency deviation error
1 kHz sine
< ± 1.5 kHz
typical content
< ± 2 kHz
Modulation power range
min.
-12 –14 dBr
Modulation power error
-6 –6 dBr
± 0.2 dBr
Pilot deviation error
6.8 kHz
± 0.2 kHz
RDS deviation range
0.8 –17.9 kHz, note 4
RDS deviation error
full signal
± 5% ± 0.5 kHz
Pilot-to-RDS phase difference error
± 4 deg.
Baseband frequency response flatness
10 Hz –60 kHz
± 0.3 dB
Stereo balance error
± 0.5 dB
Signal level (RSSI) range
typical
0 –90 dBµV
battery pwr supply
20 –90 dBµV
Signal level (RSSI) error
60 dBµV
± 3 dBµV
30 –75 dBµV
± 5 dBµV
0 –90 dBµV
not specified
MPX Input
Input impedance
2.3 kΩ
Recommended source impedance
600 Ω or less
Maximum MPX level
peak to peak
8.0 Vpp
Bandwidth
-1 dB
100 kHz
Vertical resolution
12 bits
Peak to peak voltage error
1 kHz sine
± 2% ± 0.010 Vpp
Pilot level range
0.010 –2.250 Vpp
RDS level range
0.002 –3.400 Vpp
Alarm Outputs
Maximum current from pin 1
100 mA
Maximum current from/to pin 2, 3, 4, 5
15 mA (internally limited by 390R serial resistor)
Don’t open the cover (boxed versions)! No user adjustable parts inside! Risk of damage!
Never use the equipment if there's any visible damage on its electrical parts! In that case
disconnect all cables, remove accumulators and contact the vendor or manufacturer.

7
Headphones audio output
Audio channels
2 (left and right)
Output impedance
typ.
100 Ω
Output level
no load
adjustable 0.1 –4.0 Vpp @ 75 kHz
Signal to noise ratio
75 kHz dev.
60 dB
Stereo decoder separation
1 kHz
>26 dB
Distortion
1 kHz
1 %
Internal RDS/RBDS Decoder
RDS filter and demodulator
DSP based
RDS source
Antenna (RF) or MPX input
RDS groups detected
All RDS groups 0A-15A, 0B-15B
RDS services supported
PS, PI, PTY, PTYN, TP, TA, M/S, DI, AF, EON,
ECC, LIC, PIN, RT, CT, AID, RT+
RDS groups decoded
0A, 0B, 1A, 2A, 2B, 3A, 4A, 10A, 14A
Minimum RDS deviation (ΔFrds)
antenna (RF) input
1.0 kHz
Minimum RDS level
MPX input
4 mVpp
Antenna input sensitivity
(average BER = 5 % or less,
single station, no interference)
ΔFrds=2.0 kHz
25 μV
ΔFrds=3.4 kHz
18 μV
ΔFrds=6.8 kHz
9 μV
Notes (Technical specifications):
1. pp = peak-to-peak value; BER = Block Error Rate
2. Due to inherent reception the unit may have reduced sensitivity at 102.4 MHz.
3. Very strong el. field intensity (above 130 dBμV/m) may cause additional measuring error or may disallow
the measurement.
4. If pilot and RDS are not synchronized, the range reduces to 1.5 –17.9 kHz. Spurious RDS detection may
occur on stations without RDS if the station's signal is noisy or specific static sine tones are transmitted.
If ARI system is used simultaneously with RDS on the same transmitter, the RDS deviation value should
not be taken into consideration. Instead of this the Windows application and MPX spectrum graph gives an
image about signal level of each component.

8
Side connectors and controls
Following figure applies to the Al-boxed version only.
1
Input
BNC 50Ω input connector.
Accepts RF as well as MPX signal.
See section ‘Menu’ for details.
See section ‘Antenna input’ and ‘MPX input’ for specifications.
2
USB Micro
Allows connection of external 5V power supply or connection to a PC.
See section ‘Power supply’ for details.
See section ‘USB and COM Port Communication’ for details.
3
Battery holder
A space for optional battery.
Open the cover using a coin. Press and rotate clockwise to close the cover.
The unit accepts R6 AA size NiMH cells (2 pieces).
4
RS-232
Serial RS-232 connector female type.
See section ‘USB and COM Port Communication’ for pin assignment.
5
Battery off/on
Activates built-in battery voltage converter –turns on the unit if the NiMH
cells are inserted. Does not have any effect on external power supply.
See section ‘Power supply’ for details.
6
Alarm outputs (J2)
Optional alarm outputs 2.54mm (0.1") pitch pin header.
See section ‘Alarm outpus’ for details.
See section ‘Mainboard composition’ for pin assignment.
7
Headphones output
2-channel audio output provided on 3.5mm Jack.
See section ‘Headphones audio output’ for specifications.
1
76543
2

9
Power supply
Several power supply inputs are provided. They can be combined together in general but some limitations may exist.
Please read carefully all the specifications below.
USB Micro connector
Use this connector for supplying the FM analyzer from a PC computer or +5V power supply (DC wall adapter).
Maximum ripple of the power supply voltage shall not exceed 100 mVpp.
This connector is polarity protected for currents up to 2 A. Connecting the power supply the unit is always turned
on, i.e. the power off/on switch, if present, has no effect if the unit is powered via the USB connector.
The USB micro connector allows the device to be powered from various sources. To keep this
advantage, avoid strong force when using this connector. To remove dirt and restore good
conductivity, use compressed air.
Never exceed specified voltage value at this connector! It may cause permanent damage to the
device! Do not pull in and out the cable with strong force! Do not let the cable hang freely from
tables or shelves!
The USB port should be rated to full 500 mA current! When supplying the unit from USB bus, it
is a better choice to connect the unit to the USB interface on the main board. Supplies for pocket
USB hubs and for some USB interfaces of lap-top and desk top computers may not be sufficient.
Battery power supply connector
Use this connector (J13) for supplying the FM analyzer from 2x or 3x 1.2V NiMH accumulator or another low
voltage power supply (see the device specifications). When powered via the battery connector, an optional off/on
switch may control the device. Due to safety reasons, the unit does not charge the accumulators.
Performance may be impaired when the device is powered this way.
Never exceed specified voltage value at the battery power supply connector! It may cause
permanent damage to the device!
Disconnect or remove accumulators from the unit when it is not in use!
Disconnect the USB cable in order to allow operation from the battery.
Be careful not to lose the battery holder cover!
Internal power supply connectors
For embedding purposes the board provides power supply inputs at some internal connectors. These connectors are
polarity protected for currents up to 2 A. Maximum ripple of the power supply voltage shall not exceed 50 mVpp.
Connector
Pin number
Meaning
Notes
J2
(Alarm outputs)
1
+5V
Fused.
6
Ground
J3
1
Ground
4
+5V
J17
1
+5V
Preferred. Automatically disconnects USB power supply.
2
Ground
The USB Micro connector and the J2 or J3 power supply connector cannot be used at the same time (in such a case,
place a serial Schottky diode to the internal power supply path).
Never exceed specified voltage value at these connectors! It may cause permanent damage to
the device!

10
Mainboard composition
J2 –Alarm outputs / General purpose outputs *
1
+5V
2
Alarm 1 (Signal lost)
3
Alarm 2 (Silence)
4
Alarm 3 (Overmodulation)
5
Alarm 4 (Pilot or RDS level error)
6
Ground
CONLCD1 –Opt. LCD connector (HD44780, 20x4)
1
Ground
3
+5V
5
V0
7
RS
9
Ground
11
E
13
Ground
15
Ground
17
Ground
19
Ground
21
DB4
23
DB5
25
DB6
27
DB7
29
LED+
31
LED-
CONRS1 –RS-232 communication port
2
TxD
3
RxD
5
Ground
J15 –Internal RS-232 communication port
1
TxD
2
RxD
3
Ground
J1 –Internal TTL RS-232 communication port
1
RxD (TTL)
2
TxD (TTL)
3
Ground
J13 –Battery power supply connector
1
+2.2 to +4.3 V input
2
Ground
J17 –Internal 5V power supply connector
1
+5 V input
2
Ground
* Notes (Alarm outputs / General purpose outputs):
The Alarm outputs can be used as independent general purpose logical outputs or as an RDS TA output. See the
section "List of commands and configuration registers" for more details.
Maximum current from/to pins 2-5 is limited by internal 390R serial resistors.
Combined
antenna (RF)
and MPX
input
LCD
Control
interface
Alarm or
general
purpose
outputs
USB Micro
RS-232 TTL
Battery power
supply input
RS-232