Search results
Results from the WOW.Com Content Network
Schematic of an AGC used in the analog telephone network; the feedback from output level to gain is effected via a Vactrol resistive opto-isolator.. Automatic gain control (AGC) is a closed-loop feedback regulating circuit in an amplifier or chain of amplifiers, the purpose of which is to maintain a suitable signal amplitude at its output, despite variation of the signal amplitude at the input.
Astronauts manually flew Project Gemini with control sticks, but computers flew most of Project Apollo except briefly during lunar landings. [6] Each Moon flight carried two AGCs, one each in the command module and the Apollo Lunar Module, with the exception of Apollo 7 which was an Earth orbit mission and Apollo 8 which did not need a lunar module for its lunar orbit mission.
After a digital-to-analog conversion in the transmitter, the signal passes through a reconstruction filter.Then, if needed, frequency conversion is performed. The purpose of the analog tract in the receiver is to convert signal's frequency, to adjust its power via an automatic gain control circuit and to get its complex envelope components.
It was later used in the 1960s by early NASA Mars space probes and then in the Apollo Guidance Computer (AGC), [1] which was built by Raytheon. The software for the AGC was written by programmers at the Massachusetts Institute of Technology (MIT) Instrumentation Lab, and was woven into core rope memory by female workers in factories. [2]
Many different approaches and fundamental receiver "block diagrams" have developed to address these several, sometimes contradictory, factors. Once these technical objectives have been achieved, the remaining design process is still complicated by considerations of economics, patent rights, and even fashion.
A block diagram is a diagram of a system in which the principal parts or functions are represented by blocks connected by lines that show the relationships of the blocks. [1] They are heavily used in engineering in hardware design , electronic design , software design , and process flow diagrams .
VisSim uses a hierarchical composition to create nested block diagrams. A typical model would consist of "virtual plants" composed of various VisSim "layers", combined if necessary with custom blocks written in C or FORTRAN. A virtual controller can be added and tuned to give desired overall system response.
A direct-conversion receiver (DCR), also known as a homodyne, synchrodyne, zero intermediate frequency or zero-IF receiver, is a radio receiver design that demodulates the incoming radio signal using synchronous detection driven by a local oscillator whose frequency is identical to, or very close to the carrier frequency of the intended signal.