泰克实时信号分析仪

Frequency Mask trigger
Software or ASIC
FPGA Hardware
-
FPGA Hardware
DPX Display processing
-
FPGA Hardware
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实时分析处理应用 信号发现 – 显示
– – – – – – – – –
RF debug RFID EMI/EMC diagnostic fault finding Interference hunting Software defined radio / radar Power Amplifier characterisation and distortion PLL /VCO ( frequency versus time) Radar Surveillance/Spectrum Monitoring
36 MHz
31 µSec
≧50 % for Span ≦ 10 MHz
20 µSec
≧50 %
20 nSec
RSA 3300B
15 MHz
41 µSec
≧50 % for spans ≦ 10 MHz
Base-band Processing (ASIC,
ADC
I/Q Demodulator ADC
VCO LNA
FPGA,DSP
…)
Down Conversion
Receiver
I Q
11011011
t
I Q Analog I/Q
t
t IF RF
11011011 t Digital I/Q
ASIC=Application Specific Integrated Circuit; FPGA=Field Programmable Gate Array; DSP=Digital Signal Processor, ADC=Analog-Digital Converter; DAC=Digital-Analog Converter; VCO=Voltage Controlled Oscillator; LNA=Low Noise Amplifier
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数字射频挑战
时间因素不能被忽略了
数字射频有新的挑战
– 新的时域测试项目
– 什么时间跳到另外一个信道 ? – 什么时间发射更高速率 ? – 脉冲信号的参数如何随时间变化? 其他一些智能无线技术的普及（LTE），信号发射速率， 调制方式等参数都是随着时间变化的。 Time Domain
泰克实时信号分析仪
钱永. 实时信号分析仪技术支持工程师
内容
现代数字世界为什么需要实时信号分析仪（瞬态信号，跳频，脉冲，所有随时 间变化的信号 实时真正的意思是什么？ 实时的关键技术是什么？ 应用的领域
– Wireless communications
– GSM/EDGE/W-CDMA/W-LAN /WiMax /LTE/MIMO
频率模板触发. 泰克专利技术.

Define a frequency mask which can be used to trigger on specific events in the frequency domain Reliably detect and capture elusive RF signals that a level trigger cannot see in a crowded spectral environment
DPX™ 频谱 – 实时射频信号显示
Typical Spectrum Viewing
- Misses true behavior of time-varying signals - Low probability of intercept for fast events - Signal persistency cannot be viewed
“The unique real-time presentation of live RF signals means that a user will always find a problem signal.” – David Saar, Saar Consulting
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Real-Time Bandwidth
Post Capture Processing
The Real-Time Difference
Real-Time Spectrum Analyzer (RTSA)
Real-Time Bandwidth 5 7/24/2013 Tektronix Confidential
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实时分析处理应用 信号发现 – 显示
实时显示可以发现多种复杂信号
多个RFID标签和读写器信号
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为何需要触发
为什么触发?
– 有效使用内存 – 时间相关

如何触发?
源自文库– – –
调制域分析
– Analog/Digital Modulation Analysis
码域分析
– Code Domain Power, Codogram – View of Code Domain Power on Code/Channel vs Time
统计分析
– – CCDF Trend analysis
RSA6000
40 MHz
31 µSec
≧50 % for spans ≦10 MHz
30.1 µSec
≧50 %
20 nSec
RSA6000 Opt 110 RSA 3408B
110 MHz
24 µSec
≧50 % for spans ≦ 10 MHz
10.24 µSec
≧50 %
6.67 nSec
Post Capture Processing
实时频谱如何工作
DPX技术原理
RF Transform Sample Sets DFT Spectrums Pixel Histogram Temp. Grading
Analog RF To Digital Conversion
Discrete Fourier Transform
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VSA + RSA 比较表
Functional Block VSA RSA
Amplitude/Phase correction
Software
FPGA Hardware
Digital downconversion + IQ Demodulation
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分析仪的简单框图
Swept Tuned Spectrum Analyzer (SA)
Vector Signal Analyzer (VSA)
Digital Filter ADC Memory DSP
Modern FFT Based Analyzers
Pixel Buffer Memory
Display Color Grading
RF Input
Up to 102.4 MSPS RSA3000 300 MSPS RSA6100
(DFT Computation is Completed Before Next Sample Set)
Real-Time Spectrum Analysis
>48,000 DFT/s
>1400 DFT/Frame
10 Frames/s RSA3000 33 Frame/s RSA6100
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独特的实时频谱（DPX技术）
比一般分析仪快500倍
– 看到别人看不到的信号
Same input signal
Min Pulse Duration for 100% probability of discovery
DFT overlap
Min Pulse duration for 100% probability of trigger
DFT overlap
Minimum pulse duration for 100% probability of trigger at widest BW
* At specified amplitude and spectrum accuracy, spectral events short than the minimum event duration are not specified, but can still be captured at lower accuracy and probability
Computer World
–
传统的频域测试项目
– – 发射信号频率 ? 信号功率 ?
Frequency Domain
Wireless World
Digital RF Transmitter / Receiver
RF VCO Baseband Signal Proces sing ADC I/Q Demodulator Down Conversion LNA ADC

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频率模板触发. 泰克专利技术
频域上根据需要定义触发模板 快速触发信号，达到10 微妙 捕获带宽可达110MHz
Set Mask around all known signals
Trigger on unwanted signals
– 功率触发
– 外部触发 – 频率模板触发 (FMT)
– 设置模板，然后捕获有用信号
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无线信号捕获后进行后分析
在五个域上进行分析
– – 频域分析
– DPX™ Spectrum, Spectrum, Spectrogram
时域分析
– – Frequency vs Time, Amplitude vs Time, Phase vs Time, IQ vs Time Automatic Pulse Analysis
Real-time Spectrum Viewing
- True behavior of time-varying signals - 100% probability of intercept for signal duration as short as 24us* - Signal persistency can be viewed as variable or infinite
无线信号捕获后进行后分析
跨域分析
多种测试联合分析
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无线信号捕获后进行后分析
跨域分析
Ex: 脉冲 BPSK 信号产生频谱问题
Real-time Hardware Trace
Real-time Instruction Trace Source Code Debug

时间相关联合跨域分析
– – Signal path analysis Signal path independent
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无线信号捕获后进行后分析
频域和时域分析
时间相关联合多域分析
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工程师需要了解时域和频域的测试…
新的要求对测试工具也提出了新的挑战
7/24/2013 Tektronix Confidential
Digital
Analog
无线无处不在, 数字射频测试
从基带到射频的完整测试
Time Domain (Digital)
Time Domain (Analog) Frequency Domain
Trace back to line of Code!
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百分百捕获信号最小驻留时间和DFT帧重叠
Model
Max Acquisition Bandwidth
DPX
Frequency Mask Trigger
Power/Level Trigger