|
In general terms, in the classical super regenerative receiver, the RF oscillation obtained at the output of the oscillator is applied to a non-linear detector followed by a low pass filter.
The principle of super regenerative receiver is based on the theory of quenching, where a quench oscillator causes repeated build up and decay of oscillations and the oscillations are maximum at the zero crossing where the quench signal goes towards the positive half cycle.
The super regenerative detector stage operates simultaneously at three frequencies: the radio frequency of interest, the super sonic quench frequency, and the the audio or baseband frequency.
The super-regenerative detector constitutes a sampled-data system; that is, each quench period samples and amplifies the RF signal.
These were popular in the early days of RC model airplanes because of low parts count, low weight and low power consumption.
In modern times they have found applications in short range sensor and radio control, such as garage door opener receivers and wireless key less locks.
The next step up is the synchronous super regenerative receiver. In this application the quench frequency is much lower and a PLL is required.
But it still has the advantage of low parts count and low power consumption and of course good sensitivity.
|