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l FFT
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l EMI
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Amp
Digital I/ODigital I/O
Digital I/O DAC
RF Tx Out
System IndicatorSystem
Indicator
I2C/SPI CLK
I2C/SPI DATA
Mic
ro-C
ontr
olle
r Uni
tPLL PLL
FiltersFilters
PLL Ref Osc Processing Control
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lllll FFT
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FFT 0Hz DC-1/2 .FFT
FFT
FFT :
(FFT )
FFT )
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R&S RTO FFT
FFTFFT
RTO :
FFT )
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RTO FFT
I RTC FPGAI
FFT
ADCAmp
MATH
RTC
FPGAFFT
CPU
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l FFTlll
FFT 1 FFT 2 FFT 3 FFT 4
single acquisition
FFT 1FFT 2
FFT 3FFT 450% overlapping
RTO FFT
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FFT vs FFTf(x)
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f(x)
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f(x)
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f(x)
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f(x)
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f(x)
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f(x)
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f(x)
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f(x)
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f(x)
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windowing
FFT FFT
…
FFT
… …
+
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RTO FFT
FFT
FFTFFT
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II ADCI ADC ADC (as artifacts in FFT spectrum)II
I RTOI ENOB> 7 bitsI
I 1/4I >60dB
RTO FFT
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: 500 MHz -25dBm: 5mV/div & 2us/div
FFT : Center Freq = 1GHz, Span of 1GHz, Resolution BW 100kHz
10Gs/s
1 2
3 410GS/s ADC 10GS/s ADC
1
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:
•
Example:
Sample rate = 10Gs/s Frequency Span = 10 MHz
In bits this means:
100010
/10MHz
sGspanFrequencyS
SampleRateGainDecimation
9.9)1000(2LogGainBits
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1) :
Example: 256 averages lowers the noise floor about 24 dB
2) .
Memory depth = Magnitude of asynchronous noise = Dynamic range
Example: x2 Memory depth = -3 dB of noise
dBLogdBNLogdBN avgfl 24)256(*3)(*3 22
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Averaging OFF FD Averaging ON, Count = 256
100 MHz CW Carrier, -10 dBm
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Averaging OFF TD Averaging ON, Count = 256
100 MHz CW Carrier, -10 dBm
24 dB
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Record Length: 1 kSa Record Length: 10 kSa Record Length: 100 kSa
10 MHz CW Carrier, -10 dBm
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RTO FFT
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Center = 2,4 GHz Span = 50 MHz
Fast frequency hopper100.000 hop/sec
Gated FFT view to analyze the durationof each frequency setting
11 hop frequencies, 1 MHz spacing, 10 us interval
FFT view ofentire record
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RTO
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EMI
RTO
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Center = 2,4 GHz Span = 50 MHz
(THD)
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Center = 2,4 GHz Span = 50 MHz
Fast frequency hopper100.000 hop/sec
Gated FFT view to analyze the durationof each frequency setting
11 hop frequencies, 1 MHz spacing, 10 us interval
Fast hopping frequency synthesizer
FFT view ofentire record
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– AM
Center = 245 kHz Span = 10 kHz Center = 5 kHz Span = 10 kHz
245 kHz AM modulated carrier
1 kHz modulation signal
AM modulated carrier
Modulation signal + harmonics
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– FM
Center = 96.5 MHz Span = 1 MHz
96.5 MHz FM modulated carrier
1 kHz modulation rate250 kHz deviation
FM deviation
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– GSM burst
Center = 850 MHz Span = 2 MHz
Single GSM timeslot
FFT envelope mode
FFT normal mode
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– WLAN 802.11g
Center = 2.4 GHz Span = 50 MHz
Bluetooth Signal hidden behind 802.11b WLAN Signal
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Center = 2,4 GHz Span = 50 MHz
500 MHz Carrier
Pulse period 10 usPulse width 1 us Span = 20 MHz
Span = 4 MHz
Pulse Width
Pulse Period
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VCO
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PLL #1
VCO Input = 1.9V
830MHz 830MHz 830MHz
VCO RF
FFT
SPI
MOSISPI
VCO
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PLL #1
VCO Input
830MHz 830MHz 840MHz
VCO RF
Gated FFTFrequency Domain
SPI Clock
MOSI
Protocol Decode
SPI Serial bus ControlSignal to VCO
1.9V2.7V
480us PLL Settling Time
480us PLL Settling Time
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l VCO
- VCO
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l VCO
1
4 VCO
- VCO
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Use SmartGrid for easier viewing
- VCO
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l VCO
Use SmartGrid for easier viewing
FFT
FFT
- VCO
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Use SmartGrid for easier viewing
2.397GHz 2.4GHz
- VCO
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- VCO
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l VCO
!!!
- VCO
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l FFT
2 gated FFT Full FFT
- VCO
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FFT
- VCO
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EMI
EMI l EMI
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ll RTO
l HZ-15
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EMI
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-DUT EMI EMI
l-- EMI
Electric field Probe Magnetic field Probe
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PCB
/
EMI
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40MHz Clk Chip
40MHz
, 40MHz
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EMI -
MOFET -
Less Occur
Frequently Occur
MOFETLC
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EMI – FFT
400ns Pulse
Gated FFT
FFT
Gated FFT
Time Domain
Time Domain
Frequency Domain
Frequency Domain
130MHz
100MHz180MHz
200MHz
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EMC
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9KHz-1MHz• Conducted Emission using LISN
• 9 kHz – 1 MHz
• FSV trace 1 = Max hold / Pos Peak RTO FFT1 = Normal mode
• FSV trace 2 = Clear Write / Auto Peak RTO FFT2 = Envelope mode
EN55015Q
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EMI
l FFT EMI
Oscilloscope FFT
ESPI EMI Tester
NOTE:
EMIEMI
ESPI EMI Tester
ESPI EMI Tester
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Center = 2,4 GHz Span = 50 MHz
FFT FFT
FFT
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RTO
EMI