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9-4: Intermediate Frequency and Images
Direct Conversion Receivers
A special version of the superheterodyne is known as the direct conversion (DC) or zero IF (ZIF) receiver.
DC receivers convert the incoming signal directly to baseband without converting to an IF.
They perform demodulation as part of the translation.
The low-noise amplifier (LNA) boosts the signal before the mixer.
The local oscillator (LO) frequency is set to the frequency of the incoming signal.
Baseband output is passed via a low-pass filter (LPF).