Automatic gain control for an HF Doppler radar receiver by J. D. Forberg

Cover of: Automatic gain control for an HF Doppler radar receiver | J. D. Forberg

Published by U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories in Boulder, Colo .

Written in English

Read online

Subjects:

  • Automatic gain control.,
  • Doppler radar.

Edition Notes

Book details

StatementJ.D. Forberg, B.L. Weber.
SeriesNOAA technical memorandum ERL WPL -- 104.
ContributionsWeber, B. L., Environmental Research Laboratories (U.S.)
The Physical Object
Paginationiii, 27 p. :
Number of Pages27
ID Numbers
Open LibraryOL15265880M

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Get this from a library. Automatic gain control for an HF Doppler radar receiver. [J D Forberg; B L Weber; Environmental Research Laboratories (U.S.),].

In an HF Doppler radar system to remotely measure surface currents and waves on the ocean. One important hardware component is the HF receiver, which must have a large dynamic range of sensitivity. The automatic gain control (AGC) algorithm which is used to adjust that sensitivity is Author: J.

Forberg, B. Weber. Automatic gain control (AGC) is one of the most common gain recovery methods in seismic processing. AGC is applied to the seismic data on a trace-by-trace basis using a sliding time window. Fig. shows the principle of AGC application. A window with a length of Δt is selected (Fig.

A), and this window is progressively moved down along the time axis sample-by-sample (e.g., Fig. What is AGC in receiver. Automatic Gain Control Methods. Most radar receivers use some means to control the overall gain. This usually involves the gain of one or more IF amplifier stages.

Manual gain control by the operator is the simplest method. •STC (sensitivity time control): gain as a function of time (range) •AGC (automatic gain control): may not used due to unavailability of low-noise amplifiers and excellent of RF mixers protect the sensitive mixer from saturation or burned •Noncoherent: •Low IF: lower cost •High IF: Wideband Chapter 7: Radar Receiver 7 - 3 Dr.

Sheng File Size: 1MB. The automatic gain control (AGC) is a feed-forward instantaneous type. This gain control circuit matches the signal's rms value to the range of the analog-to-digital (A/D) converter (at the output of the video amplifiers); otherwise many more bits would be required in the A/D converter, with the severe consequence of limiting the time of conversion from the analog level to the digital word.

Doppler Radar sends radio waves in the 10 to 50MHz band and listens to the scattered signal from the surface waves that have wavelengths in the 15 to 3m range; The Unique Nature of HF Radar High-frequency (HF) radio formally spans the band MHz (with wavelengths between 10 meters at the upper end and meters at the lower end.

Radar Functions • Normal radar functions: 1. range (from pulse delay) 2. velocity (from Doppler frequency shift) 3. angular direction (from antenna pointing) • Signature analysis and inverse scattering: 4. target size (from magnitude of return) 5. target shape and components (return as a function of direction) 6.

moving parts (modulation of. In a bistatic pulse radar, the receiver is equipped with its own antenna in a different location as the has the advantage that the receiver can operate without significant protective measures against to a high transmission power.

In the simplest case, a network is constructed from extra receiver locations to an existing monostatic pulse radar. Clutter Doppler Frequency. Clutter spreads in the Doppler domain due to platform motion. As the radar moves past two point targets from B to A, the doppler shift will vary approximately linearly with time, passing the zero frequency at boresight for zero squint.

This Doppler shift approximates to a linear chirp, as the platform moves past the targets. More common video enhancement featuresassociated with radar receivers such as Automatic Gain Control (AGC) [3] were adopted, where the gain control was necessary to adjust the receiver.

An Introduction to Radar and the Super Dual Auroral Radar Network* (with an emphasis on the Kodiak SuperDARN) *The intention of this collection of slides is to provide the novice with a self-guided introduction to the Super Dual Auroral Radar Network – what it is and why it is.

The book covers: target and clutter cross-section characteristics, prediction, and measurement; antenna technology ranging from modern reflector antennas to electronically steered phased arrays, low-sidelobe antennas, and adaptive antennas; and, airborne pulse doppler, AMTI, and MTI radar methods for the detection of aircraft in the midst of.

Automatic Gain Control, AGC. Audio amplifier: Once demodulated, the recovered audio is applied to an audio amplifier block to be amplified to the required level for loudspeakers or headphones.

Alternatively the recovered modulation may be used for other applications whereupon it is processed in the required way by a specific circuit block.

Radar is an object-detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain.A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the.

Or radar may only be able to paint the targets with very less sensitivity (faint echoes). On JRC radar, to perform the performance test, go to Test PM on. This will change the radar range to Increase the gain to full and you can see plume on the radar.

Also you can see the bar on the bottom right corner of the radar. Automatic gain control (AGC) units increase the dynamic range of a system to compensate for the limited dynamic range of analog to digital converters.

This problem is compounded in wireless systems in which large changes in signal strength are effects of a changing environment.

These issues are evident in the direct-conversion Doppler radar vital- sign monitor. Microwave Components, Polarization, Radar Equations, Radiation Patterns, Receiver Characteristics, Receiver Sensitivity, Receiver Tests, Radio Frequency Components, RS Interface, RS Balanced Voltage Interface, RS Interface, Transmission Control Protocol SECURITY CLASSIFICATION OF: LIMITATION OF ABSTRACT SAR NUMBER OF PAGES.

We propose a novel digitally based automatic gain control mechanism for HF transceivers, along with a pulse shaping mechanism to suit. The system directly digitises the output waveform, and can allow for low-latency protection and gain control.

Output transmit pulses need to have a smooth envelope, in order to maintain a well-behaved frequency spectrum. An adaptive automatic gain control (AGC) system (also referred to as an adaptive sensitivity time control) is disclosed for pulsed radar applications to reduce the input dynamic range requirements to a doppler signal processor by forming a "running average" of a video signal along a range sweep over a succession of range bins and forming a "running average" over corresponding.

This paper researches on some key technologies of anti-jamming of an air-borne radar receiver, the automatic testing of AGC, IAGC and multi-filtering under one million noisy pulses by the computer simulation system.

The system tests the width of the jamming pulse whose width is % bigger, 60% bigger and % smaller than the Radar signal’s respectively and show the SNR curve. COMINT Portable RF Record/Playback, Simulation, Search Receiver 5 1GbE • 1 Rx & 1 Tx or 2 Rx or 2 Tx • 1 MHz – 8 GHz with 40/80 MHz IBW • 8 dB NF, & 93 dB Gain Control • 16 Bit data converters • FPGA based programmable DDC & DUC for BW selection from 5 kHz to 40/80 MHz • 2 TB SSDs for real-time record & playback.

Reduces Radar Detection Range Automatic gain control adjust out interference and detection range. Activates Radar Interference Detected Circuits Some models stop processing speeds if interference detected.

Mask Legitimate Targets Masking multiple Doppler filters. Produces False Speed Readings If interfering signal falls in a single Doppler filter.

When a real aircraft enters the range of the RADAR, its strong target turns the gain down where it belongs, and the anomalous targets disappear. On one early RADAR set, an upgrade moved the gain control to a different control knob, and changed the old gain knob to become the automatic gain control adjustment.

But operators often forgot. Ultra-wideband (also known as UWB, ultra wideband, ultra-wide band and ultraband) is a radio technology that can use a very low energy level for short-range, high-bandwidth communications over a large portion of the radio spectrum.

UWB has traditional applications in non-cooperative radar recent applications target sensor data collection, precision locating and tracking. will also look at the operation and use of aircraft radio and radar antennas. Learners will gain an understanding amplifiers, filters, automatic gain control (AGC), automatic frequency control (AFC), demodulators; typical receiver specifications eg image channel rejection.

Automatic Gain Control-AGC. This page describes Automatic Gain Control(AGC) algorithm basics which monitors received signal and controls gain automatically in a receiver. AGC which stands for Automatic Gain Control is very useful in any receiver especially in the handset or mobile side. As the signal transmitted from Base Station reaches to the.

This free App on Radar & Sonar Engineering covers most important topics in simple English and diagrams for a quick study and revisions at the time of Exams, Viva, Assignments and Job interviews. It is the most useful App for last minute preparations. The best app for school, college and work.

If you are a student It will help to learn a lot. This useful App lists topics in 5 chapters. A CFAR receiver, no matter whether it is an automatic device or an operator controlling the receiver gain, maintains the false-alarm rate constant by reducing the probability of detection.

When the threshold level is raised to maintain a constant false-alarm rate, marginal echo signals that might normally be detected do not cross the higher. Automatic Gain Control.

Closed-loop control of the receiver gain. In tracking radars, Manual Gain Control: control of the receiver gain performed manually by the operator.

Over The Horizon (Backscatter). A radar working in the HF range (from MHz to tens of MHz) exploiting ionospheric scattering to achieve over-the-horizon performances. But, as the signal gain is increased, the target is “gained out” with the jamming signals and no target is displayed.

This is called velocity bin masking and can completely deny target information to a pulse Doppler radar. The advantage of narrowband Doppler noise is that it completely masks an aircraft's velocity from a pulse Doppler radar. resolution, Automatic Gain Control (AGC) settling time of the receiver, peak power, frequency stability, phase noise of the local oscillator (LO) and all pulse parameters.

The AGC circuit of the receiver protects the radar from overload conditions due to nearby collocated radars or jamming countermeasures. The attack and decay time of. A pulse Doppler radar receiver is disclosed wherein monopulse sum and difference signals are time-multiplexed and passed through a single gain-controlled amplifier channel for normalization, the sum signal being processed to provide both a D.C.

gain control signal for such channel and a reference signal for demodulating the difference signal. AUTOMATIC GAIN CONTROL - See AGC. Frequency Input Output f f f L M H Strength Strength 0 dB - dB f f f For a radar receiver, it is the difference between the two frequencies at which the receiver response that arise from the type of detection and console display employed in pulse Doppler and MTI receivers.

BISTATIC RADAR - A radar using. The data acquisition control server also accepts commands to configure the signals that control the radar transceiver state, such as (i) transmit pulse length and triggering waveform, (ii) high voltage modulator enable and disable, (iii) receiver gain settings, (iv) transmit pulse sampling, and (v) internal noise source enabling.

In radio equipment, Automatic Frequency Control (AFC), also called Automatic Fine Tuning (AFT), is a method or circuit to automatically keep a resonant circuit tuned to the frequency of an incoming radio is primarily used in radio receivers to keep the receiver tuned to.

AGC (AUTOMATIC GAIN CONTROL) – A method for automatically obtaining an essentially constant receiver output amplitude. The amplitude of the received signal in the range gate determines the AGC bias (a DC voltage) which controls the receiver gain so as to maintain a nearly constant output even though the amplitude of the input signal changes.

Automatic Gain Control (AGC) Most radar receivers use some means to control the overall gain. This usually involves the gain of one or more IF amplifier stages. Manual gain control by the operator is the simplest method. Usually, some more complex form of automatic gain control (agc) or instantaneous automatic gain control (iagc) is used during.

Butterworth-Heinemann’s Aircraft Engineering Principles and Practice Series provides students, apprentices and practicing aerospace professionals with the definitive resources to advance their aircraft engineering maintenance studies and career. This book provides an introduction to the principles of communications and navigation systems.

It is written for anyone pursuing a career in. Radar is a detection system that uses radio waves to determine the range, angle, or velocity of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain.A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain, a transmitting antenna, a receiving antenna (often the same.

Different types of Antennas in RADAR SYSTEM Polarization Antenna Radiation The Doppler Effect CW Radar Range and Doppler Measurement Frequency-modulated RADAR FM-CW radar using sideband superheterodyne receiver FM-CW radar with signal-following superheterodyne receiver FM-CW technique for eliminating the.Abstract: The invention relates to a radar system comprising a transmitter with a periodically tunable HF-transmitter tube, as a magnetron with rotating tuning body, and a receiver with a mixing stage, in which echo pulses caused by transmitted radar pulses are mixed with the output signal from a local oscillator, whose frequency can be.An airborne early warning moving target indicator radar in which targets in the main beam having reflective characteristics sufficient to override side lobe attenuation are tracked relative to the side lobes and the residual doppler frequency for such targets resulting from side lobe detection calculated.

Based on this calculation, the appropriate ones of a bank of doppler filters are.

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