hello Mr Richardson
Modem is a what not a who. A computer modem is a device that uses an analog carrier signal to encode digital information. The modem is how you connect to dial up Internet.
Analog Modulation
A modem is a modulator and demodulator device that modulates the analog carrier signal to encode the digital information and demodulates the signal to decode the transmitted information. The modem usually produces a signal that can be transmitted easily and decoded to reproduce the original data.
by analog to digital,digital to analog signal
Modem (from modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. That is the definition of Layer 1.
There is no modulation of a Digital Circuit.Modulation is placing information onto an analog circuit to transport thatinformation to a distant location to be decoded/demodulated.Having said that, you can modulate a digital signal in dozens of ways,(Modem) and you can also modulate an analog signal dozens of ways(AM Radio Station, CB Radio, Walkie Talkie, FM Rock Station).NoteWhat this question may really be asking about is something like:"What are the differences between using an analog signal and a digital signal when you want to encode some information for transmission?"so that has now been posted as a separate question.
Amplitude in data communication refers to the size or magnitude of a signal. It represents the strength or intensity of the signal, typically measured as the difference between the peak and trough of a waveform. In analog transmission, amplitude modulation (AM) alters the amplitude of a carrier wave to encode information.
A USB broadband modem can be used for quite a number of various purposes. Its primary purpose and most common use is modulating an analog carrier signal to encode digital information.
An DAC convert digital signal to analog signal i.e Digital to Analog Converter. An ADC convert analog signal to digital signal i.e Analog to Digital Converter.
AM (amplitude modulation) is the most susceptible to noise among the three analog-to-analog conversion techniques. This is because noise primarily affects the amplitude of the signal, leading to interference and distortions in the received signal. In contrast, FM (frequency modulation) and PM (phase modulation) are less susceptible to noise as they encode information in frequency and phase variations, respectively, which can be more effectively separated from noise during reception.
They are a method of storing information, but as there is no computer or digitizing element involved, it is not exactly a digital signal. It is an analog signal.
When you convert digital signal to analog, it is called as an analog signal. The device used is called digital to analog converter.