Modulation is converted into the baseband signal transmission signal technology. It will sample the analog signal after quantization, a binary digital signal "1" or "0" on-off modulated light carrier, and the pulse code (PCM). Digital modulation has the advantage of strong anti-interference relay when the impact of noise and dispersion does not accumulate, so you can achieve long distance transmission. The disadvantage is the need to wide band devices also are complex.
Basic Definitions
Baseband signal is the original signal, generally refers to the basic waveform, in digital communication modulation technique
In refers to the corresponding electrical pulses. In the wireless telemetry and radio remote control system is to use technology in the modulation baseband frequency carrier signal control parameters (amplitude, frequency and phase), these parameters change with the baseband signal. Parameters used to control high-frequency carrier signal is called modulation baseband signal. Unmodulated high-frequency oscillations called the carrier (which may be sinusoidal, or non-sine wave, square wave, pulse sequences, etc.).
Explanation
The modulated signal modulated high-frequency oscillations called modulated wave or modulated signals. Modulated signal is transmitted through the channel to the receiver, after demodulation at the receiving end by the restoration to the original baseband signal. Demodulation is modulation of the inverse transform, is extracted from the modulated wave modulated signals. Often used in radio communications double modulation. The first step with the digital signal or analog signal to a modulated first carrier (called the sub-carrier). Or multiple multiplexed communication using modulation (frequency division multiplexing and time division multiplexing). The second step or with the modulated subcarrier multiplexed signal and then modulating a common carrier for radio transmission. The second step is called the secondary modulation modulation. Baseband signal with a frequency modulated carrier, the radio transmission can reduce the antenna size, and to facilitate long-distance transmission. Application of modulation techniques, but also improve the signal anti-jamming capability.
Basic Definitions
Baseband signal is the original signal, generally refers to the basic waveform, in digital communication modulation technique
In refers to the corresponding electrical pulses. In the wireless telemetry and radio remote control system is to use technology in the modulation baseband frequency carrier signal control parameters (amplitude, frequency and phase), these parameters change with the baseband signal. Parameters used to control high-frequency carrier signal is called modulation baseband signal. Unmodulated high-frequency oscillations called the carrier (which may be sinusoidal, or non-sine wave, square wave, pulse sequences, etc.).
Explanation
The modulated signal modulated high-frequency oscillations called modulated wave or modulated signals. Modulated signal is transmitted through the channel to the receiver, after demodulation at the receiving end by the restoration to the original baseband signal. Demodulation is modulation of the inverse transform, is extracted from the modulated wave modulated signals. Often used in radio communications double modulation. The first step with the digital signal or analog signal to a modulated first carrier (called the sub-carrier). Or multiple multiplexed communication using modulation (frequency division multiplexing and time division multiplexing). The second step or with the modulated subcarrier multiplexed signal and then modulating a common carrier for radio transmission. The second step is called the secondary modulation modulation. Baseband signal with a frequency modulated carrier, the radio transmission can reduce the antenna size, and to facilitate long-distance transmission. Application of modulation techniques, but also improve the signal anti-jamming capability.
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