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This image or file is a work of a United States Department of Commerce employee, taken or made as part of that person's official duties. As a work of the U.S. federal government , the image is in the public domain .
Illustration of the spectrum of AM and SSB signals. The lower side band (LSB) spectrum is inverted compared to the baseband. As an example, a 2 kHz audio baseband signal modulated onto a 5 MHz carrier will produce a frequency of 5.002 MHz if upper side band (USB) is used or 4.998 MHz if LSB is used.
Most amateur digital modes are transmitted by inserting audio into the microphone input of a radio and using an analog scheme, such as amplitude modulation (AM), frequency modulation (FM), or single-sideband modulation (SSB). Amateur teleprinting over radio (AMTOR) D-STAR (Digital Data) a high speed (128 kbit/s), data-only mode.
The power of an AM radio signal plotted against frequency. fc is the carrier frequency, fm is the maximum modulation frequency. In radio communications, a sideband is a band of frequencies higher than or lower than the carrier frequency, that are the result of the modulation process. The sidebands carry the information transmitted by the radio ...
Note: Information in the chart has been superseded by the information in File:United States Frequency Allocations Chart 2016 - The Radio Spectrum.pdf, which was downloaded from the US Department of Commerce web site and archived at archive.org.
A Yaesu FT-857D tuned to 50.125 MHz, the traditional 6-meter single-sideband calling frequency in the United States. [1] The 6-meter band is the lowest portion of the very high frequency (VHF) radio spectrum (50.000-54.000 MHz) internationally allocated to amateur radio use. The term refers to the average signal wavelength of 6 meters. [a]
Standard time frequencies can be heard here. VHF low 54–88 MHz: vestigial sideband modulation for analog video, and FM for analog audio; 8-VSB or OFDM for digital broadcast very high frequency (VHF) band I: Channels 2 through 6 are from 54–88 MHz (except 72–76 MHz). FM radio: 87.5–108 MHz, 76–90 MHz in Japan Frequency Modulation (FM)
Single-sideband modulation with full carrier (e.g. as used by CHU) J: Single-sideband with suppressed carrier (e.g. Shortwave utility and amateur stations) K: Pulse-amplitude modulation: L: Pulse-width modulation (e.g. as used by WWVB) M: Pulse-position modulation: N: Unmodulated carrier (steady, single-frequency signal) P: Sequence of pulses ...