Injection-Locked Phase-Locked Loop for BPSK Coherent Demodulation: Theory and Design

Abstract

In this paper for the first time the use of injectionlocked phase-locked loop (ILPLL) for the BPSK to ASK coherent conversion is explored. Two circuit architectures are proposed, one using two second-harmonic ILPLL (SH-ILPLL) and the other using a single SH-ILPLL. In the case of two SH-ILPLL, feedback loop amplifiers are used and an increase of 20 times in the locking range of the converter is achieved. In the case of the single SH-ILPLL, direct BPSK to ASK conversion is also achieved but found with smaller locking and dynamic ranges. However, it is very simple and easy to develop. With the addition of an envelop detector, both circuit architectures can be used as a complete and compact RF front-end receiver that can direct demodulate digital RF/microwave signals without many intermediate components and devices. Such a low-cost and lowcomplexity receiver can be employed in many wireless applications such as RFID and sensor networks.Index Terms-Injection-locked phase-locked loops, phase and amplitude shift keying，locking range, direct demodulation.

Recent Progress of ILO-Based Novel Synchronization Techniques for Transceivers Used in Broadband Wireless Communication Systems

“…In [13][14] the tracking capability of ILO was used for BPSK to ASK coherent conversion but still with limited locking range. We extended the locking range of BPSK to ASK converter in [15] up to 20 times by using the second-harmonic injection-locked phase-locked loop (SH-ILPLL) [16]. Moving towards higher order modulation schemes, we also presented the synchronous demodulation of single-carrier QPSK signals using receiver synchronizing signals recovered by ILO method as discussed in [17].…”

“…In this paper, first, a review of our previous work described in [15] and [17] is presented. This review is important for being part of the process of the development of ILO-based synchronization technique proposed in this paper.…”

“…To widen the locking range, we used SH-ILPLL and presented mathematical analysis and simulation results for the BPSK signal coherent detection without actual carrier recovery [15]. The receiver architecture is shown in Figure 1.…”

“…Thus when combined, the ASK pattern can be obtained and further detected by a simple RF envelop detector. Details about this receiver can be found in [15]. The architecture, however, is limited to only BPSK signal detection.…”