An Ultra Broad Band Demodulator for Microwave Receiver

8/3/2019 An Ultra Broad Band Demodulator for Microwave Receiver

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An Ultra Broad bandDemodulator for Microwave

FM Receiver

Presented By:Sruthi.M.A

M1 MTV

5/1/2012

Guided By :Dr.Santhosh Kumar S


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Overview

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Introduction

Existing System

New FM Demodulator

Simulation

Experimental Verification

Conclusion


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Introduction

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Microwave Communication

Frequency Modulation

Why Frequency Modulation ?

FM Demodulators

Direct Demodulators

With Limiter & FM-AM conversionQuadrature Detector

Foster-Seeley Discriminator

Using Delay Line

Indirect Demodulator

PLL


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Existing System

Fig.1.Frequency Detector with limiter and FM-AM conversion

Fig.2.Phase Discriminator or quadrature detector

Fig.3.Detector type frequency discriminator


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Continued..

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Fig .4. Simplified block diagram of a mixer type

frequency discriminator


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Novel Frequency Demodulator

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Components

Power Splitter

Delay Line

90 Hybrid

Phase Detector

Low Pass Filter

Amplifier

Analog Multiplier

Operational Amplifier

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Demodulator Analysis

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Contd..

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Contd..


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Simulation

Fig .6. Input bit stream of a GSM signal and

demodulator output.


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Fig. 7. Photograph of the constructed setup for

evaluating the proposed demodulator

Experimental Verification

Power Splitters

42100 (Anaren)90 Hybrid

Amplitude imbalance


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Fig. 8. Evaluating setup for the proposed

demodulator

Experimental setup

Signal Generator

Frequency Modulation

capability

14- bit ADC & FIFO

Evaluation Boardsampling and recording

data


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Results

1 MHz sinusoid as modulatingsignal

Square waveform as modulatingsignal

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Fig.9. Modulating signal & DemodulatorOutput

Fig.10. Modulating signal &Demodulator Output


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Total Harmonic Distortion

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Demodulator Bandwidth

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Depends on frequency

response of baseband

stages

11.8MHz

Independent of carrier

frequencies, delay

quantities,FM

deviations


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Demodulator amplitude Response

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BER Measurement

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Network analyzerANT 20 SE

Variable gain

amplifier with

manual tuining


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Bit Error Rate

Fig. 16. BER versus input signalpower at 3 GHz

Fig.17. BER versus input signalpower at 17 GHz

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Conclusion

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New scheme for direct frequency demodulator introduced

Broadband frequency range showed no dependency on carrier frequency

No need of tuning elements

Can be implemented in IC technology with an external delay line

BER, Amplitude Response, Total Harmonic Distortion etc showed good

correspondence


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References

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1. S.R.Kurtz,Mixers as phase detectors, Watkins-JohnosonCompany, Palo Alto,CA,Tech. Note, vol. 5, no. 1,1978

2. H.Gheidi and A.Banai, Phase-noise measurement of microwave

oscillators using phase-shifterless delay-line discriminator, IEEE

Trans Microw. Theory Tech, vol. 58, no.2,pp.468-477,Feb.2010

3.


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Thank you

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Documents

An Ultra Broad Band Demodulator for Microwave Receiver