Table of Contents
How does QPSK demodulator work?
The QPSK Demodulator uses two product demodulator circuits with local oscillator, two band pass filters, two integrator circuits, and a 2-bit parallel to serial converter. Following is the diagram for the same. The two product detectors at the input of demodulator simultaneously demodulate the two BPSK signals.
What are the basic features of QPSK modulation?
QPSK Signal and Feature Parameters A QPSK signal can be expressed as where is the signal amplitude; is the carrier frequency; , , are set as 0, , , and , respectively, and the selection of is determined by the value of the base-band code.
What is the significance of the I and Q channels in a QPSK modulator?
The data rate of the Q channel is one-fourth the data rate of the I channel. As a result, the power in the Q channel should be reduced proportionally to one-fourth the level of the power in the I channel. This is accomplished by means of 6-dB attenuation in the Q channel.
What type of synchronization is used in QPSK system?
Abstract: Carrier synchronization is one of the key technologies of digital wireless communication. As a kind of four phase shift keying modulation method, QPSK has strong anti-interference ability of the suppressed carrier, which is widely used in digital wireless communications.
Why modulation and demodulation is required?
At the broadcasting station, modulation is done to transmit the audio signal over larger distances to a receiver. When the modulated wave is picked up by the radio receiver, it is necessary to recover the audio signal from it. This process is accomplished in the radio receiver and is called demodulation.
What is the limitation of QPSK?
QPSK is not more power efficient modulation technique compare to other modulation types as more power is required to transmit two bits. QPSK is more complex compared to BPSK receiver due to four states needed to recover binary data information.
How is QPSK generated?
One method of generating the QPSK waveform is by converting the input binary data stream into two streams: the odd- and the even bit streams consisting of the odd- and even numbered bits. Each of these binary streams can then be modulated using the BPSK, and then on adding we get the QPSK waveform.
What is modulation and demodulation explain in brief?
Modulation and demodulation Modulation is the process of encoding information in a transmitted signal, while demodulation is the process of extracting information from the transmitted signal.
What is the difference between modulator and demodulator?
Modulation is the process of influencing data information on the carrier, while demodulation is the recovery of original information at the distant end of the carrier. A modem is an equipment that performs both modulation and demodulation.
How do I perform QPSK modulation and demodulation?
To perform QPSK modulation and demodulation, you can use the “pskmod” and “pskdemod” functions by setting the order of modulation to 4.
What is a BPSK modulator?
At the input of the modulator, the digital data’s even bits (i.e., bits 0,2,4 and so on) are stripped from the data stream by a “bit-splitter” and are multiplied with a carrier to generate a BPSK signal (called PSKI).
What is the mathematical implementation of QPSK?
Figure below shows the block diagram of the mathematical implementation of QPSK. At the input of the modulator, the digital data’s even bits (i.e., bits 0,2,4 and so on) are stripped from the data stream by a “bit-splitter” and are multiplied with a carrier to generate a BPSK signal (called PSKI).
What is the QPSK waveform for two-bit input?
The QPSK waveform for two-bits input is as follows, which shows the modulated result for different instances of binary inputs. The QPSK Demodulator uses two product demodulator circuits with local oscillator, two band pass filters, two integrator circuits, and a 2-bit parallel to serial converter. Following is the diagram for the same.