Peak detector and RMS detector

[OMEsystem]

rms detector

What's the difference? And, when to use them in wireless system?

 

[Jim cage]

rms detector circuit

I think that both of them are the same and used for RSSI or IQ imbalance calibration. It is bascially a squarer function followed by some filters.

 

[gareth]

peak detector circuit

hy i think "HP application note on Pulsed RF" should help you...
g.

 

[flyhigh]

peak detector calculation

Hi,

not the expert in this field but I would say that the only difference might be in the time constant used in video portion of detector circuit. For peak detector the constant should be very small so that instantaneous value of the signal is detected, for RMS detector it should be long so that integrator like performance is obtained.

flyhigh

 

[OMEsystem]

rms detector peak

Hi,

not the expert in this field but I would say that the only difference might be in the time constant used in video portion of detector circuit. For peak detector the constant should be very small so that instantaneous value of the signal is detected, for RMS detector it should be long so that integrator like performance is obtained.

flyhigh

Fast charge time and slow discharge time can meet peak detector requirement?

 

[pixel]

rms peak detector difference

Peak detector measures signal amplitude.
RMS signal value is proportional to amplitude, but this coefficient depends on signal shape... i.e. peak detector, used to measure rms of sine is not any more usefull if input signal is sawtooth or pulse...
rms detectors extract rms value for all signal shapes...

 

[OMEsystem]

weighting rms detector

Do both RMS detection and Peak detection perform averaging something?

 

[sergio mariotti]

rohde schwartz rms detector

look for the following e-book, it's for free. Ask R&S.
Christoph Rauscher - Fundamentals of Spectrum Analysis - Rohde & Schwarz

Both Peak and rms detectrors (and other types) are well explained.

 

[nguyennam]

rms detector circuit in ac

Thanks Sergio for your info.

nguyennam

 

[sunart.org]

rms peak detector

Christoph Rauscher
(Volker Janssen, Roland Minihold)
Fundamentals of Spectrum Analysis


Rohde & Schwarz GmbH & Co. KG
Mühldorfstrasse 15
81671 München
Germany
www.rohde-schwarz.com
First edition 2001
Printed in Germany

This book is intended to familiarize the uninitiated reader with the field of
spectrum analysis. To understand complex measuring instruments it is
useful to know the theoretical background of spectrum analysis. Even for
the experienced user of spectrum analyzers it may be helpful to recall
some background information in order to avoid measurement errors that
are likely to be made in practice.
In addition to dealing with the fundamentals, this book provides an insight
into typical applications such as phase noise and channel power
measurements.

Table of contents
1 INTRODUCTION 9
2 SIGNALS 10
2.1 Signals displayed in time domain 10
2.2 Relationship between time and frequency domain 11
3 CONFIGURATION AND CONTROL ELEMENTS
OF A SPECTRUM ANALYZER 19
3.1 Fourier analyzer (FFT analyzer) 19
3.2 Analyzers operating according to the heterodyne principle 29
3.3 Main setting parameters 32
4 PRACTICAL REALIZATION OF AN ANALYZER
OPERATING ON THE HETERODYNE PRINCIPLE 34
4.1 RF input section (frontend) 34
4.2 IF signal processing 46
4.3 Determination of video voltage and video filters 58
4.4 Detectors 64
4.5 Trace processing 77
4.6 Parameter dependencies 80
4.6.1 Sweep time, span, resolution and video bandwidths 80
4.6.2 Reference level and RF attenuation 84
4.6.3 Overdriving 90
5 PERFORMANCE FEATURES OF SPECTRUM ANALYZERS 100
5.1 Inherent noise 100
5.2 Nonlinearities 107
5.3 Phase noise (spectral purity) 119
5.4 1 dB compression point and maximum input level 125
5.5 Dynamic range 130
5.6 Immunity to interference 142
5.7 LO feedthrough 145
5.8 Filter characteristics 146
5.9 Frequency accuracy 147
5.10 Level measurement accuracy 148
5.10.1 Error components 149
5.10.2 Calculation of total measurement uncertainty 156
5.10.3 Error due to low signal-to-noise ratio 164
5.11 Sweep time and update rate 167
6 FREQUENT MEASUREMENTS AND ENHANCED
FUNCTIONALITY 170
6.1 Phase noise measurements 170
6.1.1 Measurement procedure 170
6.1.2 Selection of resolution bandwidth 173
6.1.3 Dynamic range 175
6.2 Measurements on pulsed signals 180
6.2.1 Fundamentals 181
6.2.2 Line and envelope spectrum 186
6.2.3 Resolution filters for pulse measurements 191
6.2.4 Analyzer parameters 192
6.2.5 Pulse weighting in spurious signal measurements 194
6.2.5.1 Detectors, time constants 195
6.2.5.2 Measurement bandwidths 199
6.3 Channel and adjacent-channel power measurement 199
6.3.1 Introduction 199
6.3.2 Key parameters for adjacent-channel
power measurement 202
6.3.3 Dynamic range in adjacent-channel power measurements 203
6.3.4 Methods for adjacent-channel power measurement
using a spectrum analyzer 204
6.3.4.1 Integrated bandwidth method 204
6.3.4.2 Spectral power weighting with modulation filter
(IS-136, TETRA, WCDMA) 208
6.3.4.3 Channel power measurement in time domain 210
6.3.4.4 Spectral measurements on TDMA systems 211
MEASUREMENT TIPS
Measurements in 75 Ω system 35
Measurement on signals with DC component 39
Maximum sensitivity 106
Identification of intermodulation products 117
Improvement of input matching 155
REFERENCES 214
THE CURRENT SPECTRUM ANALYZER
MODELS FROM ROHDE & SCHWARZ 216