Cognitive Polar Receiver Using Two Injection-Locked Oscillator Stages

Abstract

Abstract-A novel cognitive polar receiver that utilizes two injection-locked oscillator stages to extract the modulation envelope and phase components of a received nonconstant envelope modulation signal without using phase-locked-loop-based carrier recovery circuitry is presented. The paper begins with a theoretical analysis of injection locking and pulling phenomena based on the discrete-time computation approach, and then develops the principles of the proposed receiver. The implemented prototype can cover a sensing bandwidth of 140 MHz at a central frequency of 2.43 GHz and perform 4 differential quadrature phase-shift keying and quadrature phase-shift keying demodulation with the best error vector magnitudes of 6.6% and 7.9%, respectively, both at a symbol rate of 2 Ms/s. Due to its simplicity, the proposed receiver has great potential as an energy-efficient architecture with low complexity for short-range wireless communications.

Gesture Sensing Using Retransmitted Wireless Communication Signals Based on Doppler Radar Technology

“…In (5), represents the injection-pulled part of the phase modulation that happens when the offset frequency exceeds the locking range, i.e., , or approaches zero near the zero crossings. Moreover, is the delay of injection locking, which depends on the difference between the free-running oscillator frequency and the received signal carrier frequency , as given by [26] ( 7) where . The ILO output signal given by (5) is further split into two quadrature signals of equal amplitude as the local oscillator (LO) signals of the quadrature mixer.…”

Human gesture sensor using ambient wireless signals based on passive radar technology

“…OJe Am ,r m s e OJL R "'-2Q A IL O ,r m s (6 ) is the locking range of the ILO with a tank qual ity factor Q. The subscript rms denotes the root mean square value of the amplitude.…”

“…In (5) , TIL is the delay of injection locking. This delay depends on the frequency offset between the injection signal and inherent oscillation signal IlOJ, as given by [6 ] (7 )…”

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“…In channel I, the local signal is given by (6) where and are the output voltage and lock-in time, respectively, of the ILO in the receiver. According to [30], is given by (7) where is the locking range of the ILO in the receiver. is the initial frequency difference between the tag and the receiver.…”