The name of the process that changes the envelope of an RF wave to convey information is amplitude modulation. A transmission that varies the instantaneous power level of the RF signal to convey information is amplitude modulation.
The name of the process that changes the phase angle of an RF wave to convey information is phase modulation. The emission produced by a reactance modulator connected to an RF power amplifier is phase modulation.
The process which changes the frequency of an RF wave to convey information is frequency modulation. When a modulating audio signal is applied to an FM transmitter the carrier frequency changes proportionally to the instantaneous amplitude of the modulating signal.
Single sideband phone emissions use the narrowest frequency bandwidth. An advantage of carrier suppression in a single-sideband phone transmission is that more transmitter power can be put into the remaining sidebands.
The signal of an over-modulated single-sideband phone transmitter becomes distorted and occupies more bandwidth. Flat-topping of a single-sideband phone transmission indicates signal distortion caused by excessive drive. Audio or microphone gain is typically adjusted for proper ALC setting on an amateur single sideband transceiver.
Both upper and lower sidebands would be found at the output of a properly adjusted balanced modulator.
Another term for the mixing of two RF signals is heterodyning. A mixer receiver stage could combine a 14.250 MHz input signal with a 13.795 MHz oscillator signal to produce a 455 kHz intermediate frequency (IF) signal. If a receiver mixes a 13.800 MHz VFO with a 14.255 MHz received signal to produce a 455 kHz intermediate frequency (IF) signal, the type of interference will a 13.345 MHz signal might produce in the receiver is called image response. A mixer stage in a transmitter would change a 5.3 MHz input signal to 14.3 MHz.
The name of the stage in a VHF FM transmitter that selects a harmonic of an HF signal to reach the desired operating frequency is the multiplier.
The total bandwidth of an FM-phone transmission having a 5 kHz deviation and a 3 kHz modulating frequency would be 16 kHz. Frequency modulated (FM) phone is not used below 29.5 MHz because the bandwidth would exceed FCC limits. The frequency deviation for a 12.21-MHz reactance-modulated oscillator in a 5-kHz deviation, 146.52-MHz FM-phone transmitter would be 416.7 Hz.
Greater keying speeds require greater frequency shifts in an FSK signal.
The 20 meter band subsegment most commonly used for PSK31 operation is below the RTTY segment, near 14.070 MHz.
RTTY, Morse code, PSK31 and packet communications have in common that they are all digital modes.
When transmitting a data mode signal, it important to know the duty cycle of the mode you are using to prevent damage to your transmitter's final output stage.