Pulse Polarity Modulation Research Articles

A Fully Integrated 0.6 Gbps Data Communication System for Inductive-Based Digital Isolator with 0.8 ns Propagation Delay and 10−15 BER

Digital isolators are implemented to protect low-voltage electronics and ensure human safety during high-voltage surge events. In this work, we present the design of an inductive-based digital isolation system that can sustain up to 1 kVrms breakdown voltage. The proposed system is designed using the pulse polarity modulation scheme and fabricated in a 0.35 μm CMOS. Two identical dies are bounded within the IC package, with one die housing the transmitter (Tx) and the isolation transformer, while the other die contains the receiver (Rx). Two different customized designs between three metal layers are implemented to form the isolation element. The transformer’s secondary coil is constructed in metal-1, while the primary coil is formed in metal-2 and metal-3 for comparing the system functionality, isolation capability, and propagation delay. The functionality has been verified by measurements for an operating frequency of 300 MHz with a 2.6 ns propagation delay and an energy consumption of 8.15 × 103 pJ/bit at 1 Mbps. The chip was tested under extreme temperatures and achieved a maximum measured common mode transient immunity (CMTI) of 500 V/μs. Jitter has been examined to ensure fast transmission at a bit error rate (BER) of 10−15 with a total jitter (TJ) of 188.18 ps.

An Open Expandable Data Protocol for Multipolar Stimulation in Cochlear Implants.

Cochlear implants (CI) have restored hearing to many deaf patients. It is the most successful neuroprosthetic in the field. However, in past decades technical improvements have plateaued and the market has solidified among 3 manufacturers. Proprietary software, and know-how are some of the barriers to innovation and disruption in CIs. In this paper we propose an open data communication protocol for cochlear implants that supports multipolar stimulation, accommodates an expandable number of channels, and minimizes the transmission of redundant information. We also present a method for implementing multipolar stimulation in single supply stimulators with a bridge-type switch matrix through pulse-polarity modulation. This combines the advantages of lower voltage (lower power) operation with more targeted stimulation.Clinical Relevance- In addition to enabling the development of new tools for research and clinical deployment, the presented data communication protocol will promote clinical research in more advanced auditory coding strategies.

A Novel Approach to All-Optical Generation of Ultra-Wideband Signals

The generation of ultra-wideband signals in the optical domain is highly desirable for ultra-wideband-over-fiber systems, which has recently become a topic of interest. In this article, a novel and simple approach to achieve all-optical generation of ultra-wideband signals is proposed, which is based on delaying and superimposing optical Gaussian pulses with opposite polarities. The proposed system is capable of generating both ultra-wideband monocycle and doublet pulses, and the polarity of the generated ultra-wideband monocycle pulses can be fast-switched to implement pulse polarity modulation with the required bit pattern. A model to describe the proposed system is developed, and the generation of ultra-wideband signals is demonstrated with simulations and a proof-of-concept experiment.

Photonic multi-shape UWB pulse generation using a semiconductor optical amplifier-based nonlinear optical loop mirror

We propose and demonstrate a scheme to implement photonic multi-shape ultra-wideband (UWB) signal generation using a semiconductor optical amplifier (SOA) based nonlinear optical loop mirror (NOLM). By employing the cross phase modulation (XPM) effect, cross gain modulation (XGM), or both, multi-shape UWB waveforms are generated including monocycle, doublet, triplet, and quadruplet pulses. Both the shapes and polarities of the generated pulses are flexible to adjust, which may be very useful in UWB pulse shape modulation and pulse polarity modulation.

All-optical UWB generation and modulation using SOA-XPM effect and DWDM-based multi-channel frequency discrimination

An all-optical UWB pulses generation and modulation scheme using cross phase modulation (XPM) effect of semiconductor optical amplifier (SOA) and DWDM-based multi-channel frequency discrimination is proposed and demonstrated, which has potential application in multiuser UWB-Over-Fiber communication systems. When a Gaussian pulse light and a wavelength-tunable CW probe light are together injected into the SOA, the probe light out from the SOA will have a temporal chirp due to SOA-XPM effect. When the chirped probe light is tuned to the slopes of single DWDM channel transmittance curve, the optical phase modulation to intensity modulation conversion is achieved at DWDM that serves as a multi-channel frequency discriminator, the inverted polarity Gaussian monocycle and doublet pulse is detected by a photodetector, respectively. If the probe lights are simultaneously aimed to different slopes of several DWDM channels, multi-channel or binary-phase-coded UWB signal generation can be acquired. Using proposed scheme, pulse amplitude modulation (PAM), pulse polarity modulation (PPM) and pulse shape modulation (PSM) to UWB pulses also can be conveniently realized.

UWB Impulse Radio Transmitter Using an Electrooptic Phase Modulator Together With a Delay Interferometer

A simple ultra-wideband (UWB) impulse radio transmitter is experimentally demonstrated using an electrooptic phase modulator (PM) and a delay interferometer (DI). By applying an electrical nonreturn-to-zero (NRZ) baseband signal to the PM, a pair of optical Gaussian pulses with opposite polarities is generated at the two output ports of the DI. By properly setting the delay between these two polarity-reversed optical Gaussian pulses using an optical delay line (ODL) component, an optical UWB monocycle pulse is generated. Pulse amplitude modulation of the UWB monocycle pulse can also be achieved by driving the PM with an NRZ baseband signal at a flexible bit rate. Experimental results verify that the proposed scheme can be used to simultaneously generate and amplitude modulate the UWB monocycle pulse. Furthermore, both the shape and polarity of the generated UWB monocycle pulse can be easily controlled by appropriately adjusting the delay of the ODL. Pulse polarity modulation of the generated UWB monocycle can also be realized by electrically switching the bias voltage of the DI.

All-optical ultra-wideband pulse generation based on semiconductor optical amplifiers

Several all-optical methods for ultra-wideband (UWB) pulse generation based on various nonlinearities of single semiconductor optical amplifiers (SOAs), namely cross phase modulation (XPM), cross gain modulation (XGM), and a hybrid of self phase modulation (SPM) and XGM, have been demonstrated. In the first method, UWB doublet pulses are realized with XPM. The input optical Gaussian pulse will be converted to two polarity-reversed monocycle pulses by a blue shifted and a red shifted optical bandpass filters respectively. These two monocycle pulses are then combined with proper time delay to generate two polarity-reversed doublet pulses. Second, two polarityreversed monocycle pulses are obtained based on XGM of the SOA and group delay of the single mode fiber (SMF). In the scheme, two polarity-reversed Gaussian pulses are generated due to XGM, and then the mixed signal is converted to a monocycle shape due to the group delay of the SMF. Finally, we present UWB doublet generation based on SPM. The monocycle pulse is generated from a dark return-to-zero (RZ) signal and converted to a doublet pulse by injecting an additional probe signal with the SMF transmission. For the first time and to the best of our knowledge, we report that the generated doublet pulses are transmitted over 5 km SMF by proper dispersion compensation without distortion. The configuration of our alloptical methods is compact and simple. The feasibility to implement the pulse shape modulation and pulse polarity modulation is discussed.

An Electrically Switchable Optical Ultrawideband Pulse Generator

A novel electrically switchable optical ultrawideband (UWB) pulse generator that is capable of generating both Gaussian monocycle and Gaussian doublet pulses by using a polarization modulator (PolM) and a fiber Bragg grating is proposed and experimentally demonstrated. The polarity and the shape of the generated UWB pulses can be electrically switched by adjusting the voltages applied to two arbitrary wave plates (AWPs), which are incorporated at the input and the output of the PolM to adjust the polarization state of the lightwaves. The key component in the UWB pulse generator is the PolM, which is a special phase modulator that can support both transverse electric and transverse magnetic modes but with opposite phase modulation indexes. Depending on the polarization state of the incident lightwave to the PolM that is linearly polarized and aligned to one principle axis of the PolM or circularly polarized, UWB monocycle or doublet pulses are generated. The polarity of the UWB pulses can be electrically switched by adjusting the voltages applied to the AWPs. The proposed system is implemented, and the generation of UWB monocycle and doublet pulses is experimentally demonstrated. Gaussian monocycle and doublet pulses with a fractional bandwidth of about 150% and 160% are experimentally generated. The proposed electrically switchable optical UWB pulse generator has the potential for applications in UWB communications and radar systems that employ pulse polarity modulation and pulse shape modulation schemes.

UWB Radio: Digital Communication with Chaotic and Impulse Wavelets

Radio communications via channels already occupied by traditional telecommunication systems can be achieved by using ultra-wideband (UWB) radio where extremely wideband wavelets are used in order to reduce the power spectral density (psd) of transmitted signal. Since the recovery of these UWB carriers is not feasible, noncoherent demodulation techniques have to be used. The letter evaluates and compares the noise performances of the feasible noncoherent UWB modulation schemes, namely, that of the noncoherent pulse polarity modulation and the transmitted reference system.

Ultrawideband Impulse Radio Signal Generation Using a High-Speed Electrooptic Phase Modulator and a Fiber-Bragg-Grating-Based Frequency Discriminator

We propose a novel approach to generating ultrawideband impulse radio signals in the optical domain. The proposed system consists of a laser source, an electrooptic phase modulator (EOPM), a fiber Bragg grating (FBG), and a photodetector (PD). The light source is phase modulated by an electrical Gaussian pulse train via the EOPM. The optical phase modulation to intensity modulation conversion is achieved by reflecting the phase modulated light at the slopes of the FBG that serves as a frequency discriminator. Electrical monocycle or doublet pulses are obtained at the output of the PD by locating the wavelength of the optical carrier at the linear or the quadrature slopes of the FBG reflection spectrum. The use of the proposed configuration to implement pulse polarity and pulse shape modulation in the optical domain is discussed. Experimental measurements in both temporal and frequency domains are presented