| 摘要 |
<p>A zero IF receiver which is capable of detecting short duration or CW signals and of operating over a large dynamic range. An embodiment of the receiver comprises an input terminal (10) for receiving an input signal, means (12, 18 to 26) coupled to the input for producing quadrature related, frequency down-converted first and second signals (I,Q). These first and second signals are applied to first and second amplifiers (28, 30) having a substantially sinh<-><1> transfer characteristics to produce substantially logarithmic output signals. First and second digitising means (32, 34) are coupled to the outputs of the first and second amplifiers (28, 30), respectively; outputs of the first and second digitising means being connected to demodulating means (36). The demodulating means (36) being constructed and operated to convert the digitised in-phase andquadrature phase signals into amplitude and frequency descriptions of the input signal relative to a centre frequency of the receiver.</p> |
