Working of the Modulator and Demodulator
The modulator is the device which changes the value of the modulated signal along with the carrier signal such that the strength of the signals can be increased either using the phase shift keying, frequency shift keying and Amplitude shift keying and the signals which is generated is specified by the QAM after combining the complex valued signal with the imaginary unit length signal and thus forms the equivalent low pass signal which is represented as the complex valued representation of the real valued modulated physical signals that sometimes either referred as the RF signal. Moreover, it involves so many steps for the data transfer using the modulator and demodulator because the modulation involves the digital to analog conversion for transferring the data on the analog lines and when it reaches the recover end then the demodulator converts this analog signal into digital signals so that computer system can easily understand the digital signals which is in form of bits that is either in zero’s form or in one’s form and data transfer over the long distance is managed and controlled by the modulator and finally at the recover end it is converted into bits by the demodulator and the device with this name is known as the Modem.
Steps involves during Modulation using Modulating device
The modulation of the data involves the strengthen of the data signals so that it can be easily transmitted over long distance and consist of the so many general steps for the modulation using the modulator for the transmission of the data and this steps is explained below-
The data which is to be transferred into breaking into partitions that is referred as the data packets and then we group these data packets that can forms the bits of codewords that consist of the symbol code for the transmission of the data signal that can map the bits of codewords to form the attributes which consist of the combined signals which forms the equivalent low pass signal using the frequency or phase values.
The other steps involves the adaption of the pulse shaping of the signal that forms the filtering action that limits the bandwidth of the signal and then forms the spectrum for the low equivalent pass signal that is typically used for the circuit analysis and the digital signal processing applications that can even perform the digital to analog conversion of the signals after strengthens the weak signals so that signal can be transmitted over the long distance.
After that the high frequency signal which consist of the sine wave characteristics have ability to generate the high frequency sine wave carrier waveform along with the cosine quadrature component for the transfer of the signals using the modulation such that multiple factor of the sine and cosine forms the equivalent low pass signal which shifted its modulated pass band signal using the data signal processing technology in which the direct digital synthesis is carried out using the waveform table in which the analog processing should be there for the data transfer. Moreover, the amplification and analog band pass is also carried out to avoid the harmonic distortion and periodic spectrum during data transfer.
Steps Involves during Demodulation using Demodulating device
Once the Modulation is completely carried out and data is transferred to the receiver end then the demodulator make use of the demodulation in which the band pass filtering is carried out which involves the automatic gain control which has reduces the attenuation problem according to which the power of the weak signal can be reduced and power can be maintained continuously using the frequency shifting that can be equivalent to the immediate frequency signal which is obtained with integration of the sine wave and cosine waveform using the local oscillator.
Then for the understanding of the data signal, the sampling is carried out in which the analog to digital conversion is there, according to which the equalization filtering action is carried out which involves the matched filter circuit for the multi-path transfer of the data using the time spreading, phase distortion and frequency selection attenuation to avoid interference and noise that has occurred during the data transfer.
Once the Amplitude of the signals are detected then integrate the frequency and phase of the IF signal using the quantization in which the three parameters that is frequency, phase and amplitude is carried out using the mapping of quantized code words that forms the parallel to serial conversion of the code words into the digital bit streams that passes the bit streams for further processing of the data that removes the error correcting codes and data can be easily understand by the receiver side and then prepares the acknowledgement for the sender.
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