Thesis on radio frequency identification

Starting around 1920 a small number of broadcasting stations began operating, and soon interest in the innovation was spreading nationwide. In the summer of 1921, a Madison Square Garden employee, Julius Hopp, devised a plan to raise charitable funds by broadcasting, from ringside, the July 2, 1921 Dempsey-Carpentier heavyweight championship fight to be held in Jersey City, New Jersey. Hopp recruited theaters and halls as listening locations that would charge admission fees to be used as charitable donations. He also contacted RCA's J. Andrew White, the acting president of the National Amateur Wireless Association (NAWA), an organization originally formed by American Marconi which had been inherited by RCA. White agreed to recruit the NAWA membership for volunteers to provide assistance at the listening sites, and also enlisted David Sarnoff for financial and technical support. RCA was authorized to set up a temporary longwave radio station, located in Hoboken a short distance from the match site, and operating under the call letters WJY . For the broadcast White and Sarnoff telephoned commentary from ringside, which was typed up and then read over the air by J. Owen Smith. The demonstration was a technical success, with a claimed audience of 300,000 listeners throughout the northeast. [15]

For SSB operation the 36 MHz signal is mixed down to 6 MHz. This 6 MHz signal is again feet into a phase comparator where it is compared to the signal of the 6 MHz VFO. This way the stable 6 MHz VFO is able to control the 36 MHz VFO which again is able to control the 96 MHz VFO. A well designed 6 MHz VFO is by far good enough for SSB, so the 96 MHz VFO in this system is good enough too. (For experts: since the time constant of the PLL loop filter is quite large, the phase noise of the 96 MHz VFO is significantly reduced also.) The frequency range of the 6 MHz oscillator is only 500 kHz, but this is completely sufficient since all SSB/CW operation is located in the 144 – MHz area.

Thesis on radio frequency identification

thesis on radio frequency identification

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