What signal property is adjusted in modulation for effective data transmission?

In modulation for effective data transmission, all three signal properties—frequency, amplitude, and phase—can be adjusted to encode information onto a carrier signal.

Frequency modulation (FM) changes the frequency of the signal in accordance with the data being transmitted. This method is commonly used in radio broadcasting and is effective in providing resistance to noise and signal distortion.

Amplitude modulation (AM) varies the amplitude of the carrier signal to represent the data, which is a straightforward approach widely used in applications like AM radio. This method alters the strength of the signal depending on the information being sent.

Phase modulation (PM) alters the phase of the carrier signal, allowing for the transmission of data. It can be more complex but enables efficient use of bandwidth and increases data transmission rates.

Since modulation can involve adjusting any or all of these properties based on the method and requirements of the communication system, the correct choice encompasses all options. This versatility allows for various modulation schemes to be tailored to different applications and environments, thus facilitating effective data transmission.