Notepad/enter/Radio.md

Rhode and Schwarz Presentations 

  

Presentation 1: James 

- EmC presentations - gtime FFT 
    

- Emissions 
    

Summary: 

- Compliance testing is required for most electrical devices 
    

- Failure rate in full compliance is quite  high 
    
- Redesign + retest is retired 
    

- Precompliance testing is very important 
    

  

Questions: 

- Anyone melted a probe? (people have definitely melted antennas) 
    

  
  

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Signal Generators 

  
  

Topics: 

- Primary purpose of signal generators 
    
- Produces electrical wave forms of various a mplitudes, frequency and phase properties 
    

- Signal sinusoidal (CW - Continuous wave, SMW-2WA - the “flagship” Signal Generator) 
    

  

Why are they important? 

- They provide close to ideal input signals to the device under test (DUE_ 
    
- They emulate real-worls signals in the case of complex - moulations 5G, LTE, Wifi 
    

- Good performance ois important to minimize generators 
    

  
  

Signal Generators → 1. Analog Generators 2. Digital Generators 

Analog Signal Generators 

- Frequency, basic modulation, boise and spectral p
    
- Major reason for switching to analog 
    

  

Veector Signal Generators 

- Frequency and level range 
    
- Noise and spectral purity → modulation BW + capabilities 
    

  

Analog 

  

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Vector 

  

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What do we need an analog generator for 

- High quality singals 
    
- Reference code 
    
- Gain 
    
- Component development / testing (ADCD_ 
    
- Receiver testing 
    
- Military / radar applications 
    

  
  
  

AM  Frequency modulation    FM frequency modulation Phase freqeuncy modulation 

  
  

Analog Generator Selection Criterai -- things to consider 

  

Primary: 

- Frequency range 
    
- Phase-noise 
    
- Harmonics 
    
- Output power 
    

  

Secondaru 

- Switching speeds 
    
- Frequency + amplitude accuracy 
    
- Very bad modulation support 
    

- Very important to understand your input signals 
    

  
  

Vector Signal Generator Applciations 

- Receiver testing - a huge applications 
    
- Impairment generation 
    
- Impulse testing 
    
- Fading capbiliites, ability to generate attenuated delayed signals 
    
- Radar echo preparations (GNSS)
    
- Multipath signal generators
    

  
  

Vecotr Signal Basics: 

- Analog signals defined by magnitude 
    
- Vector signals defined by: magnitude + phase 
    

- Used in digita modulation 
    

- LTE, SGNR, Wifi, Bluetooth, SatCOM 
    

  

ASK, PSK, FSK 

  

Generating IQ Values 

- Start with Symbol that represents particular magnitude _ phase 
    
- Magnitude + phase can be converted into can be converted into 
    

- In-phase (“real”) 
    
- Quadratic (“imaginary”) 
    

- Simplifies the pair of IQ vzlaues 
    

  

IQ Modulatior 

- Converts base band (transmitting) signals into RF Signals 
    
- This allows the AM FM PM to sum the signals 
    

  
  

IQ Modulation Steps  

- Many licensing keys that you buy/input 
    
- ca n bring data in digitally (bring the IQ values in digitally) - various  ways to define the baseband 
    
- Can have a file of IQ values 
    
- Specific data that has been mapped to IQ values 
    

- Appropriate IQ values are generated based on what you selected 
    
- Seiteis fo steps involved in creating a vector modulated signal 
    
- Basic Digital Modulation - each variations of a signal magnitude _ phase represent a unique symbol 
    

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Each symbol  represents a specific  digital bit or combination of  bits  - 

ASL - Amplitude  of  100%  and 50% 

BPSK - phase 0 degrees and 180 degrees 

  
  
  

Constellations (Symbol Mapping) 

- Constellations - collection of symbols on a polar chart representing a signal and magnitude and phase 
    
- X - acist depicting amplitude (I ) 
    
- Y -  as  depicting phase (Q) 
    
- ASK depicts 2 symbols with 1 bit of info - modulating in amplitude 
    

- BPSK chart depicts 2 symbols molulating only in phase 
    

  
  

How do we add more bits/symbols/information for faster data transmission? 

- Through QAM symbol mapping 
    
- Could transmit only 1 bit previously can transmit 4 bits now! 
    
- These mits make up the frame of  our wifi, transmission, bluetooth, etc.. 
    

  
  
  
  

Modulation Bandwidth 

- Some LTE at least 10 MHz of bandwidth requires 
- Frequency - generators RF frequency , usually the carrier signal  
- Bandwidth 
- ** important tto distinguish what the signal rate is and what the bit-rate is **
- Flatness is the gain variation of the  platform 
    

  

Impairment Generation 

- Another huge reason for vector 
- previously  talked about band base generation  
- Able to do fading and noise injection 
    

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- impairment s emulate real-world effects 
- Keeps up with standards as well 
- Base band impairments - noise - SW interferes - impulse noise - phase noice - 
- Fading - ability t o generate copies of a signal , attenuate them, or dopplegang them 
    

  
  

AWFN impairments 

- Additive white gaissian noise additive -
- Additive Combine dwith useful 
- White: noise constant other frequency 
- Gaussian - describes how noise changes over time ODFM (orthogonal) 
- 23 ASK Constellations   ODFM orthogonal  
- Considered more immune than QM 
- Device under test → mini circuits amplification 

  

AWGN Generation 

- Constellation drawn by the analyzer 
    
- Analyzer (receiver basically) no trouble achieving 
    
- Signal to rnoise ratio - APSK (PVB -52, Digital Viceo Broad cast 
    
- This  is  very important for devices that  are  re-timing the circuit 
    
- Needs to be able to filter out the (phase) noise that you inject 
    

  
  

Phase noise impairment:

- Anything coming up in time domain (called jitter) 
    
- Anything long0term in time domain (called wonder) 
    
- Excessive phase noise can cause many issues 
    
- Disturbance  in communication systems for instance
    
- Phase noise can be addes to base bands signal by 
    
- Define amount of phase noise at gain  - frequency offsets 
    
- Adding phase noise to signal leads to rotation
    
- Errors → adjacent signal  /  symbols  bleeding into other symbols - bit-error 
    

  

Impulse Noise impairment - many real wprld examples of impulse noise impairment 

- unintentional - spark plugs motors, 
    
- Intentional - radars, or bursty , modulation time 
    

  
  
  

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