Sidebands, AM Power, and Amplitude Modulation Techniques

Vocabulary practice flashcards covering AM sidebands, bandwidth, power calculations, modulation techniques (SSSC, DSSC, VSB), and radio emission classifications.

Sidebands

New frequencies generated directly above and below the carrier frequency after a carrier signal is modulated by an information signal.

Spectrum Analyzer

A test instrument used to display the frequency domain of a signal by plotting signal amplitude versus frequency.

Upper Sideband Frequency ($f_{USB}$)

The sideband frequency calculated as $f_{USB} = f_c + f_m$, where $f_c$ is the carrier frequency and $f_m$ is the modulating frequency.

Lower Sideband Frequency ($f_{LSB}$)

The sideband frequency calculated as $f_{LSB} = f_c - f_m$, where $f_c$ is the carrier frequency and $f_m$ is the modulating frequency.

Amplitude Shift Keying (ASK)

Amplitude modulation produced when complex signals such as square waves or rectangular pulses modulate a carrier signal.

On-Off Keying (OOK)

Continuous-wave (CW) transmission achieved by switching the carrier signal off and on, as in Morse code transmission.

Splatter

Harmonic sideband interference resulting from overmodulation in AM signals.

Total AM Power ($P_T$)

The total transmitted power in an antenna, calculated as $P_T = P_C + P_{USB} + P_{LSB}$, or $P_T = P_C \times \frac{1 + m^2}{2}$ where $P_C$ is carrier power and $m$ is the modulation index.

Modulated Antenna Current ($I_T$)

The total antenna current in a modulated AM system, calculated using $I_T = I_C \times \frac{\sqrt{1 + m^2}}{2}$, where $I_C$ is the unmodulated antenna current and $m$ is the modulation index.

Single-Sideband Suppressed Carrier Modulation (SSSC)

A type of amplitude modulation where the carrier and one sideband are removed or suppressed, leaving only one sideband for transmission.

Double-Sideband Suppressed Carrier Modulation (DSSC)

A type of amplitude modulation where only the carrier is removed and both sidebands are transmitted.

Balanced Modulator

A circuit used to generate Double-Sideband Suppressed Carrier (DSSC) signals.

Vestigial-Sideband Modulation (VSB)

A modulation technique in which one sideband is transmitted along with a small portion (vestige) of the other sideband.

Pilot Carrier

A low-level carrier signal transmitted alongside an SSB signal to enable easy carrier re-insertion and demodulation at the receiver.

Peak Envelope Power (PEP)

The maximum power produced on voice amplitude signals in SSB transmission, calculated by the formula $PEP = \frac{V_{rms}^2}{R}$.

Average Power ($P_{avg}$)

The normal range of power transmitted when typical human speech is modulated onto the carrier in SSB transmission, calculated as $P_{avg} = \frac{PEP}{4}$ to $P_{avg} = \frac{PEP}{3}$.

Emission Code Designation A3

Radio emission code designating Double-Sideband (DSB) with two sidebands and full carrier.

Emission Code Designation A3b

Radio emission code designating Double-Sideband (DSB) with two sidebands and suppressed carrier.

Emission Code Designation A3j

Radio emission code designating Single-Sideband (SSB) with single sideband and suppressed carrier.

Emission Code Designation A3a

Radio emission code designating Single-Sideband (SSB) with single sideband and $10\%$ pilot carrier.

Emission Code Designation A3c

Radio emission code designating Vestigial sideband TV.

Emission Code Designation A1

Radio emission code designating On-Off Keying (OOK) and Amplitude Shift Keying (ASK).

ITU Emission Designation A3F

International Telecommunications Union designation for amplitude-modulated analog TV.

ITU Emission Designation J3E

International Telecommunications Union designation for SSB voice transmission.

ITU Emission Designation F2D

International Telecommunications Union designation for FSK data transmission.

ITU Emission Designation G7E

International Telecommunications Union designation for phase-modulated voice with multiple signals.