Post on 25-Jul-2015
transcript
Narda Safety Test Solutions
Firma: Narda Safety Test Solutions GmbHName: Holger SchwarzAdresse: Sandwiesenstrasse 7
72795 PfullingenGermany
Telefone: +49 7121 9732 724Fax: +49 7121 9732 790E-Mail: holger.schwarz@narda-sts.deInternet: www.narda-sts.de
What is major difference between broadband and selective measurement?
Broadband meter measures the sum of emissions for all services
Spectrum Analysis measures the emission
service by service
e.g. NBM and Probe Type EF0691
e.g. SRM Spectrum Analysis
Bandwidth 100 kHz to 6 GHz (means 5.9999 GHz
fixed)
From 10 Hz to 20 MHz
variable
Center frequency
2.99995 GHz fixed From 9 kHz to 6 GHz
variable
Two Challenges on Test Equipment
1. Sensitivity, specially for measurementsAt HomeIn OfficesIn Public Areas
2. BandwidthCompared to previous Systems modern Communication System occupy higher Bandwidth e.g.:
• DVB-T• UMTS• LTE (4G)• …
1. Sensitivity
No problem for workplace safety measurements. There is “sufficient” field strength to by measured by broadband equipment
1. Sensitivity
ICNIRP/RPS3 and Italy
1,00
10,00
100,00
1000,00
10E+3 100E+3 1E+6 10E+6 100E+6 1E+9 10E+9 100E+9 1E+12Frequency / Hz
E / (
V/m
)
ICNIRP Occupational, Australia "RF Worker"
ICNIRP General Public, Australia "NON-RF Worker"
Exposure limits for general public Italy
Attention thresholds and quality targets Italy
1. Sensitivity
0.1 mV/m
0.01 V/m
1000 V/m
100 V/m
10 V/m
1 V/m
0.1 V/m
1 mV/m
Spectrum Analyzer (1 kHz RBW)
200 V/m
60 µV/m
Broadband (3 GHz probe)
320 V/m
0.2 V/m
RF Limit Values
6 V/m (Italy)
27 V/m
Typical indoor and publicmeasurement values
2. Bandwidth
Bandwidth of services is growing rapidly!Bandwidth of services is growing rapidly!
GSM: bandwidth
200 kHz
3G: bandwidth
5 MHz
Analog: bandwidth
3.1 kHz
LTE (4G): bandwidth
20 MHz
2. Bandwidth, Broadband Equipment
AdvantageIt’s broadband:
3, 6, 18 or even 50 GHz bandwidth is no problem
DisadvantageIt’s broadband:
It doesn’t tell you who it isIt’s sensitivity is limited
2. Bandwidth, Selective Equipment
AdvantageIt’s narrowband:
Distinction between different services is no problemSensitivity is high enough to measure even very small signals
DisadvantageIt’s narrowband:
Bandwidth might not be big enough to capture a complete signal of one of the new services
Bandwidth RBW
Which Bandwidth (RBW) has to be selected?
In spectrum analysis a RBW which is equal to the bandwidth of the service you want to measure
Bandwidth of Service < RBW Okay, but the measurement result can also include other services
Bandwidth of Service = RBW Best
Bandwidth of Service > RBW Indication of the marker will be smaller than the total amount. Better to use integration “Integration over frequency”
Examples of occupied Bandwidth
E.G.:LW/MW/SW 10 kHzDRM 4,5 to 20 kHzFM Radio 200 kHzGSM traffic or BCCH 200 kHzDAB 1,5 MHzUMTS 5 MHzAnalog TV 5-8 MHzDVB-T 7 MHzLTE (4G) 1.4, 3, 5, 10, 15, 20 MHzSRM can offer bandwidth from 10 Hz up to 20/32 MHz
RBW available
in traditional handheld SA
GSM Time Slot
Facts of GSM:Each GSM-antenna has one Signaling Channel (BCCH) and several Traffic ChannelsEach Channel has a Bandwidth of 200 kHzGSM Traffic Channel has 8 Time Slots each 577 µs
DECT
Facts of DECT PhonesFrequency Range: 1880 – 1900 MHzBase Station: permanently onChannel Structure: Number of Channels: 10 Channel Bandwidth 1.728 MHz (f = 1897.344 - n * 1.728 MHz)Cycle Duration: 10 ms with 24 Time Slots each 368 µs
W-LAN Facts
Frequency Range• 2.4 GHz - 2.497 GHz • 5.15 GHz - 5.35 GHz • 5.725 GHz - 5.825 GHz
Channel Structure: Channel Number
• 2.4 GHz: 14 (overlapping), 3 (non-overlapping)• 5 GHz: 12 (non-overlapping)
Channel Bandwidth• 20 MHz but also 10 MHz and 40 MHz (most 16.6 MHz or 20 MHz)
Cycle Duration: 0.25 ms up to 1 … 2ms
Summary of technical details
Channel Bandwidth: 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHzDL Multiple Access: OFDMADuplexing: FDD and TDDSub-carrier spacing: 15 kHz
Data Modulation: QPSK, 16QAM, 64 QAMFFT size (5MHz): 512Channel Coding: Convolutional coding and turbo codingMIMO: Multi layer pre-coded spatial multi-placing space time / frequency block coding, switched transmit diversity, and cycle delay diversity
LTE - Technical Definition
BANDWIDTHBandwidth between 1.4 to 20 MHz (variable) (1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, 20 MHz)