Contents
* Preface
* General Theory
o Signals in Radio Astronomy
+ Introduction
+ Properties of the Gaussian
+ The Wiener-Khinchin Theorem
+ The Sampling Theorem
+ The Central Limit and Pairing Theorems
+ Quasimonochromatic and Complex Signals
+ Cross Correlations
+ Mathematical details
o Interferometry and Aperture Synthesis
+ Introduction
+ The Radio Sky
+ Signals in Radio Astronomy
+ Interferometry
# The Need for Interferometry
# The Van Cittert Zernike Theorem
# Aperture Synthesis
+ The Fourier Transform
o Single Dish Radio Telescopes
+ Introduction
+ EM Wave Basics
+ Signals and Noise in Radio Astronomy
# Signals
# Noise
# Signal to Noise Ratio
+ Antenna Patterns
+ Computing Antenna Patterns
o Two Element Interferometers
+ Introduction
+ A Two Element Interferometer
+ Response to Quasi-Monochromatic Radiation
+ Two Element Interferometers in Practice
o Sensitivity and Calibration for Interferometers
+ Sensitivity
+ Calibration
+ Further Reading
o Phased Arrays
+ Introduction
+ Array Theory
# The 2 Element Array
# Linear Arrays of n Elements of Equal Amplitude and Spacing :
# The Fourier Transform Approach to Array Patterns
+ Techniques for Phasing an Array
+ Coherently vs Incoherently Phased Array
+ Comparison of Phased Array with a Multi-Element Interferometer
+ Further Reading
o Imaging With Dipolar Arrays
+ Early History of Dipole Arrays
+ Image Formation
+ Digital Beam Forming
+ Radio Telescopes with Digital Beam Forming Networks
# The Clark Lake TEE-PEE-TEE Telescope
# GEETEE: The Gauribidanur Array
# MOST: The Molonglo Observatory Synthesis Telescope
# Summary
+ Square Kilometer Array (SKA) Concept
+ Adaptive Beam Forming
+ Further Reading
o Correlator I. Basics
+ Introduction
+ Digitization
# Sampling
# Quantization
# Dynamic Range
+ Discrete Fourier Transform
# Filtering and Windowing
+ Digital Delay
+ Discrete Correlation and the Power Spectral Density
+ Further Reading
o Correlator - II: Implementation
+ Delay Tracking and Fringe Stopping
+ Spectral Correlator
# FX Correlator
# XF Correlator
+ Further Reading
o Mapping I
+ Coordinate Systems
# Angular Co-ordinates
# Astronomical Co-ordinate System
# Physical Coordinate System
# Coordinate Transformation
+ 2D Relation Between Sky and Aperture Planes
+ Further Reading
o Mapping II
+ Introduction
+ Weighting, Tapering and Beam Shaping
+ Gridding and Interpolation
+ Bandwidth Smearing
+ Time Average Smearing
+ Zero-spacing Problem
+ Further Reading
o Deconvolution in sythesis imaging-an introduction
+ Preliminaries
+ The Deconvolution Problem
# Interferometric Measurements
# Dirty Map and Dirty Beam
# The Need for Deconvolution
+ CLEAN
# The Högbom Algorithm
# The Behaviour of CLEAN
# Beyond CLEAN
+ Maximum Entropy
# Bayesian Statistical Inference
# MEM Images
# Noise and Residuals
+ Further Reading
o Spectral Line Observations
+ Spectral Lines
+ Rest Frequency and Observing Frequency
+ Setting the Observing Frequency and the Bandwidth
+ Calibration
# Gain Calibration
# Bandshape Calibration
+ Smoothing
+ Continuum Subtraction
+ Line Profiles
+ Further Reading
o Wide Field Imaging
+ Introduction
+ Mapping with Non Co-planar Arrays
# Image Volume
# Interpretation of the -term
# Inversion Of Visibilities
+ Mosaicing
# Scanning Interferometer
+ Further Reading
o Polarimetry
+ Introduction
+ Polarization in Radio Astronomy
+ The Measurement Equation
+ Polarization Calibration
+ Further Reading
o Ionospheric effects in Radio Astronomy
+ Introduction
+ Propagation Through a Homogeneous Plasma
+ Propagation Through a Smooth Ionosphere
+ Propagation Through an Inhomogeneous Ionosphere
+ Angular Broadening
+ Scintillation
+ Further Reading
o Pulsar Observations
+ Introduction
+ Requirements for Pulsar Observations
# Phased Array Requirements
# Spectral Resolution Requirements
# Requirements for Time Resolution and Accurate Time Keeping
# Requirements for Polarimetry
# Flux Calibration Requirements
+ Basic Block Diagram of a Pulsar Receiver
+ Dispersion and Techniques for its Correction
+ Pulse Studies
+ Interstellar Scintillation Studies
+ Pulsar Timing Studies
+ Pulsar Search
+ Further Reading
* The GMRT
o An Overview of the GMRT
+ Introduction
+ Array Configuration
+ Receiver System
+ Digital Backends
o GMRT Antennas and Feeds
+ Introduction
+ Types of Antennas
+ Characterizing Reflector Antennas
+ Computing Reflector Antenna Radiation Patterns
# Aperture Efficiency
+ Design Specifications for the GMRT Antennas
# Secondary Patterns
+ GMRT Feeds
# Feed Placement
# 150 MHz Feed
# 327 MHz Feed
# Dual-Frequency Coaxial Waveguide Feed
+ 1000-1450 MHz Feed
+ GMRT Antenna Efficiencies
+ Further Reading
o The GMRT Servo System
+ Introduction
+ Objectives of the GMRT Servo System
+ The GMRT Servo System Specifications
+ Control System Description
# Closed Loop Control Systems
# Principles of Position Control
# Position Loop Amplifier
# Rate Loop Amplifier
# Current Loop Amplifier
+ Servo Amplifiers
+ Servo Motors
+ Gear Reducers
+ Position Sensors
+ Dual Drive
+ Digital Controller
+ Servo Operational Commands
o GMRT Receivers
+ Introduction
+ Overview of the GMRT Receiver Chain
+ Receiver Design Considerations
+ The Multi Frequency Front Ends
+ The Antenna Base Receiver
+ The Fiber-Optic Link
o The GMRT Optical Fiber System
+ Introduction
+ The Laser Transmitter
# Laser Specifications
+ The Optical Fiber
+ The Optical Receiver
+ Link Performance
o Local Oscillator and Base-band Systems
+ Requirement for a Local Oscillator System at the GMRT
+ The Frequency Translation Scheme used at the GMRT
+ Generation of Phase-Coherent Local Oscillator Signals
+ Noise Calibration and Walsh Switching
+ The Base-band System
+ A Summary of Important Specifications
# Array Frequency Reference
# First LO Synthesiser
# Second and Third LO Sources and Offset Frequency Sources
# Fourth LO Synthesiser
# Base-band System
o A Control and Monitor System for the GMRT
+ Introduction
+ Overview
# ONLINE
# PCROUTER
# COMH
# ANTCOM or ABC
# Servo Control Computer
# Monitor and Control Modules
+ Signal Flow in the GMRT Control & Monitor System
# Error Detection
+ Signal Modulation
# Frequency Shift Keying
+ System specifications of the Control & Monitor system
# Overview
# Bit rates available for various services
# Details of the various communication links
o The GMRT Correlator
+ Introduction
+ An overview of the GMRT Correlator
# ADC
# Delay-DPC
# FFT
# MAC
+ Modes of operation of the GMRT correlator
# Non-Polar Mode
# Indian-Polar Mode
# Polar Mode
+ Further Reading
o The Data Acquisition System for the GMRT
+ Data Acquisition
+ Correlator Control
+ Monitoring the health of the correlator
+ Online processing of the data
# The network of acquisition and processing
# The software layout
# Time stamping of data and it's accuracy
+ Further desirable features
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