RF Source Basic.ppt

1、RF Seminar,RF Source Basics,Title of Presentation 7/27/2004,Page 2,Agenda,Types of sources CW Swept Signal Generator Block Diagrams Applications Specifications,Title of Presentation 7/27/2004,Page 3,Sources Generate Sine Waves,Voltage,Time,Voltage,Frequency,This is the ideal output: most specs deal

2、with deviations from the ideal and adding modulation to a sine wave,RF,Microwave,Millimeter,20-50 GHz,300 GHz,3-6 GHz,Spectrum Analyzer,Oscilloscope,Title of Presentation 7/27/2004,Page 4,Types of Sources,CW generates a single frequency, fixed sine wave Swept sweeps over a range of frequencies may b

3、e phase continuous Signal Generator adds modulation produces “real world” signal,Title of Presentation 7/27/2004,Page 5,Agenda,Types of sources CW Swept Signal Generator Block Diagrams Applications Specifications,Title of Presentation 7/27/2004,Page 6,CW Source Specifications .Frequency,Voltage,Freq

4、uency,Uncertainty,Range: Range of frequencies covered by the source Resolution: Smallest frequency increment. Accuracy: How accurately can the source frequency be set.,EXAMPLE Accuracy = =CW frequency = 1 GHz =aging rate = 0.152 ppm/year =time since last calibrated = 1 year,*,*,Title of Presentation

5、 7/27/2004,Page 7,CW Source Specifications .Amplitude,DUT,Source protected from accidental transmission from DUT,Voltage,Frequency,How accurate is this number?,What is P out?,What is P out?,max,min,Range (-136dBm to +13dBm) Accuracy (+/- 0.5dB) Resolution (0.02dB) Switching Speed (25ms) Reverse Powe

6、r Protection,Title of Presentation 7/27/2004,Page 8,Phase Noise Residual FM Spurious,CW Source Specifications .Spectral Purity,non-harmonic spur 65dBc,harmonic spur 30dBc,CW output,Residual FM is the integrated phase noise over 300 Hz - 3 kHz BW,phase noise,0.5 f0 f0 2f0,sub-harmonics,Title of Prese

7、ntation 7/27/2004,Page 9,CW Source Specifications . Spectral Purity: Phase Noise,CW output,frequency,Power Spectral Density,measured as dBc/Hz,Ch1 PM PSD,1k,10k,100k,TRACE A:,A Marker,10 000 Hz,75 dBc/Hz,-125 dBc/Hz,LogMag,5 dBc/div,-105 dBc/Hz,Title of Presentation 7/27/2004,Page 10,RF CW Block Dia

8、gram,Reference Oscillator,f,VCO,Phase Detector,Frac-N,divide by X,ALC Modulator,ALC Driver,ALC Detector,Output Attenuator,ALC = automatic level control,Reference Section,Synthesizer Section,Output Section,Title of Presentation 7/27/2004,Page 11,RF CW Block Diagram Reference Section,f,Phase Detector,

9、Optional External Reference Input,Reference Oscillator (TCXO or OCXO),TCXO,OCXO,Aging Rate,+/- 2ppm/year,+/- 0.1 ppm /year,Temp.,+/- 1ppm,+/- 0.01 ppm,Line Voltage,+/- 0.5ppm,+/- 0.001 ppm,to synthesizer section,divide by X,Title of Presentation 7/27/2004,Page 12,RF CW Block Diagram Synthesizer Sect

10、ion,f,VCO,Phase Detector,Frac-N,from reference section,to output section,X 2,multiplier,Front panel control,5MHz,465.5 MHz,N = 93.1,931 MHz,5MHz,.produces accurate, clean signals,Title of Presentation 7/27/2004,Page 13,RF CW Block Diagram Synthesizer Section,reference oscillator,phase noise of sourc

11、e,VCO noise,phase detector noise,broadband noise floor,20logN,phase-locked-loop (PLL) bandwidth selected for optimum noise performance,PLL / Fractional - N .suppresses phase noise,noise,Title of Presentation 7/27/2004,Page 14,RF CW Block Diagram Output Section,ALC = automatic level control,ALC Modul

12、ator,ALC Driver,ALC Detector,Output Attenuator,from synthesizer section,source output,ALC maintains output power by adding/subtracting power as needed Output Attenuator mechanical or electronic provides attentuation to achieve wide output range (e.g. -136dBm to +13dBm),Title of Presentation 7/27/200

13、4,Page 15,mWave CW Block Diagram,ALC Detector,Sampler,Reference Section,Synthesizer Section,Output Section,Ref Osc,f,VCO,Phase Det,Frac N,by X,f,VCO,Phase Detector,Frac-N,f,Phase Detector,Tuning Coils,YIG Oscillator,Title of Presentation 7/27/2004,Page 16,Applications 25frames/sec,slot 1 slot 2 slot

14、 3 slot 4 slot 5 slot 6,324 bit (162 symbols) = 6.667ms,G R Data Sync Data SACCH CDVCC Data 6 6 16 28 122 12 12 122,Mobile to Base Station,Title of Presentation 7/27/2004,Page 51,Applications and Critical Specifications Analog and Digital,Receiver Sensitivity frequency accuracy level accuracy error

15、vector magnitude Receiver Selectivity phase noise spurious spectral accuracy Spectral Regrowth ACP performance,Title of Presentation 7/27/2004,Page 52,Applications and Critical Specifications Receiver Sensitivity,Frequency Accuracy,Title of Presentation 7/27/2004,Page 53,Applications and Critical Sp

16、ecifications Receiver Sensitivity,Customer is testing a -110 dB sensitivity pager:,Power Out,-110 dB specification,Case 1: Source has +/-5 dB of output power accuracy at -100 to -120 dBm output power.,Set source to -115 dBm,Actual output power= -114 dBm,X,X,X,X,X,O,Case 2: Source has +/-1 dB of outp

17、ut power accuracy at -100 to -120 dBm output power.,Power Out,-110 dB specification,Set source to -111 dBm,Actual output power= -112 dBm,X,X,O,O,O,O,X= Failed unit,O=Passed unit,Frequency,Frequency,Level Accuracy,Title of Presentation 7/27/2004,Page 54,Applications and Critical Specifications Receiv

18、er Sensitivity,Error Vector Magnitude (EVM),Title of Presentation 7/27/2004,Page 55,Applications and Critical Specifications Receiver Selectivity,Phase Noise Spurious,Title of Presentation 7/27/2004,Page 56,Applications and Critical Specifications Receiver Selectivity,Spectral Accuracy: EVM ACP,Title of Presentation 7/27/2004,Page 57,Applications and Critical Specifications Spectral Regrowth,Input from signal generator,Output from amplifier,ACP Performance,Title of Presentation 7/27/2004,Page 58,Agilent Families of Signal Generators,RF,Microwave,Agilent 8647/48 fa