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 is nonzero receiver?
The continuous wave radar with non zero IF provides isolation between transmitter and receiver. Separate antennas are used for transmission and reception to reduce the signal leakage. Local Oscillator provides the carrier signal whose frequency is equal to intermediate frequency.
What is IF stage in receiver?
Intermediate frequencies are used in superheterodyne radio receivers, in which an incoming signal is shifted to an IF for amplification before final detection is done. When several stages of filters are used, they can all be set to a fixed frequency, which makes them easier to build and to tune.
What is IF and RF?
An RF (or IF) mixer (not to be confused with video and audio mixers) is an active or passive device that converts a signal from one frequency to another. These three ports are the radio frequency (RF) input, the local oscillator (LO) input, and the intermediate frequency (IF) output.
What is meant by LO leakage?
The local oscillator (LO), which drives the mixer, has leaked to the mixer’s output port. There are also other paths for the LO to leak to the system output, such as through power supplies or across the silicon itself. Regardless of how the LO leaks out, it can be referred to as LOL.
What is the difference between heterodyne and homodyne?
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 is low if architecture?
Low-IF receiver topologies have many of the desirable properties of zero-IF architectures, but avoid the DC offset and 1/f noise problems. The use of a non-zero IF re-introduces the image issue. Image signal and unwanted blockers can be rejected by quadrature down-conversion (complex mixing) and subsequent filtering.
What is if explain its function in receiver?
In communications and electronic engineering, an intermediate frequency (IF) is a frequency to which a carrier wave is shifted as an intermediate step in transmission or reception. A variable local oscillator is used in the receiver to hold the difference-signal center frequency constant as the receiver is tuned.
What is the use of IF in receiver?
Intermediate-frequency (IF) amplifiers are amplifier stages used to raise signal levels in radio and television receivers, at frequencies intermediate to the higher radio-frequency (RF) signal from the antenna and the lower (baseband) audio or video frequency that the receiver is recovering.
Why if is used in receiver?
The use of an IF simplifies the design of tunable receivers and reduces the number of components that must be compatible with high frequencies. IF architectures simplify the design of bandpass filters because the reduced center frequency results in a lower Q-factor requirement.
What is the function of IF stage?
Why is zero-i f receiver architecture so popular?
The zero-IF receiver architecture is also attractive because it can ease demodulation of very wideband RF signals. Q: If zero-I F eliminates circuitry and has other virtues, why isn’t it used more often?
What is a zero if transceiver?
The transceiver based on this zero IF architecture is known as zero IF transceiver . • All the filtering is carried out at baseband and hence analog filtering used in heterodyne architecture is alleviated here. Digital filters are easier to design. Moreover they are less expensive compare to RF/IF analog filters.
What is a zero IF frequency?
This reduces the IF frequency to zero or near zero, rather than standard values such as 455 kHz. Fig 1: In the zero-IF architecture, the tuned signal is downconverted directly to baseband by mixing it with an LO at or near the carrier frequency, thus eliminating the need for an IF stage.
What is a zero IF oscillator?
A: Zero-IF, sometimes called a direct conversion or homodyne architecture, uses a local oscillator which is set equal to the desired carrier frequency being tuned, or very close to it, Figure 1. This reduces the IF frequency to zero or near zero, rather than standard values such as 455 kHz.
