LOW IF Receiver
the low-IF or digital IF receiver. A low-
IF receiver downconverts the desired spectrum directly from RF to some very low-IF
(typically < few 10s of MHz). The advantages of using a low-IF over a zero-IF is that
this eliminates the issues of DC offsets and reduces susceptibility to 1/f noise. Low-
IF receivers can also be highly integrated, since filtering can be done on-chip while
maintaining high performance . In addition, the down converted spectrum is at
a low enough frequency that it can be easily sampled by low-power analog-to-digital
converters (ADC), and is thus also known as digital IF. The spectrum may then be
converted to baseband using digital signal processing (DSP). However, with low-IF
receivers, as with heterodyne receivers, comes the issue of image rejection. Due to
the difficulties in achieving sharp-cutoff analog BPFs with low-power consumption for
image rejection, designers have pursued image-cancelling architectures. Two popular
image-cancellation receivers are the Hartley and Weaver architectures.