Super-regenerative receiver is one of the potential candidates to achieve ultra low power wireless communication in body area network (BAN). The main limitations of the super-regenerative receiver include the difficulty in choosing a good quench waveform to optimize its sensitivity and selectivity, and its significantly degraded performance in the presence of interference. To address the above problems, we first propose a novel quench waveform search algorithm providing good sensitivity and selectivity results. The algorithm avoids the undesirable manual calibration and hence suitable for autonomous operation. In addition, we consider the spectrum sensing algorithm to autonomously avoid data transmission in the presence of unacceptable interferences. The above algorithms enabling autonomous operation of the super-regenerative receiver are implemented in hardware. Our measurement results show that by using the quench waveform calibrated super-regenerative receiver, the system can provide stable probability or missed-detection and probability of false alarm results in different carrier frequencies. This is very desirable for the determination of a good threshold in spectrum sensing. Together with our previously reported chip designed for the super-regenerative receiver, we have developed an autonomously operating super-regenerative receiver based wireless system, which is ideal for many BAN applications.