Contents
What is homodyne detection in optical communication?
Homodyne Detection For optical homodyne measurements, both waves are virtually always derived from the same laser source. The homodyne technique is phase-sensitive in the sense that the power of the heterodyne signal depends on the relative phase of signal and local oscillator, and may even totally vanish.
What is difference between homodyne and heterodyne?
The basic difference between Homodyne and Heterodyne Detection is based on the signal carrier and local oscillator frequency. In homodyne detection signal carrier and local oscillator frequency is equal i.e. ωif = 0 and In heterodyne detection signal frequency and carrier frequency are not equal i.e. ωif ≠0.
What do u mean by heterodyne?
A heterodyne is a signal frequency that is created by combining or mixing two other frequencies using a signal processing technique called heterodyning, which was invented by Canadian inventor-engineer Reginald Fessenden. The new signal frequencies are called heterodynes.
How does a direct conversion receiver work?
Direct-conversion receivers typically filter and amplify a received RF input signal. The signal then enters a mixer along with a local-oscillator (LO) signal that is identical in frequency to the RF input signal. Thus, the input signal is converted to a 0-Hz signal that appears at the output of the mixer.
What is direct detection?
A direct-detection (DD) system is a communication system based on detecting modulated optical power (also referred to as the optical field intensity or simply the optical intensity). Therefore such systems are often referred to as intensity-modulation and direct-detection (IM-DD) systems.
What is the main difference between super heterodyne and homodyne receiver?
In Heterodyne receiver, it requires one mixer to bring the modulated RF signal to modulated IF signal, which is applied to I/Q demodulator which brings the modulated low IF to baseband at zero IF. In super heterodyne receiver, it requires two mixers to bring the modulated RF signal to modulated-IF signal.
Why it is called superheterodyne receiver?
On that receiver, the two signals mixed just as they did in the original heterodyne concept, producing an output that is the difference in frequency between the two signals. In this case, all of the frequencies are well beyond the audible range, and thus “supersonic”, giving rise to the name superheterodyne.
What are the advantages of superheterodyne receiver?
The superheterodyne receiver offers superior sensitivity, frequency stability and selectivity. Compared with the tuned radio frequency receiver (TRF) design, superhets offer better stability because a tuneable oscillator is more easily realized than a tuneable amplifier.
What is direct conversion method?
A direct-conversion receiver (DCR), also known as homodyne, synchrodyne, or zero-IF receiver, is a radio receiver design that demodulates the incoming radio signal using synchronous detection driven by a local oscillator whose frequency is identical to, or very close to the carrier frequency of the intended signal.
What are the advantages and disadvantages of a homodyne receiver?
It mentions Homodyne receiver advantages or benefits and Homodyne receiver disadvantages or drawbacks. What is Homodyne Receiver? Homodyne receiver does not use any RF mixer for conversion of modulated RF signal to baseband I/Q signals. The baseband signals are at zero frequencies. The figure-1 depicts Homodyne Receiver architecture.
What kind of RF mixer does a homodyne receiver use?
Homodyne receiver does not use any RF mixer for conversion of modulated RF signal to baseband I/Q signals. The baseband signals are at zero frequencies. The figure-1 depicts Homodyne Receiver architecture. Homodyne receiver uses LO (Local Oscillator) frequency of same value as received signal frequency.
What’s the difference between a homodyne and heterodyne transceiver?
The homodyne receiver is also known as direct conversion receiver. The main problem in this type of receiver is LO leakage. This LO leakage need to be as low as possible in order to make RF Transceiver work efficiently to deliver baseband I/Q signals. Also refer advantages and disadvantages of Homodyne receiver >> and Heterodye receiver >> types.
How does a super heterodyne receiver work?
In super heterodyne receiver, it requires two mixers to bring the modulated RF signal to modulated-IF signal. The first mixer brings RF signal to high IF signal and the later mixer brings high IF signal to low IF signal. This is applied to I/Q demodulator which brings the low IF signal to zero IF baseband signals.