scholarly journals Demonstration of a Duplex Microwave Photonic Filter and Its Reconfigurability in a Frequency Range of 0–10 GHz

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2159
Author(s):  
Leidy Johana Quintero-Rodríguez ◽  
José Roberto Warnes-Lora ◽  
Min Won Lee ◽  
Jorge Rodríguez-Asomoza ◽  
Ignacio Enrique Zaldívar-Huerta
Keyword(s):  
Signal To Noise Ratio ◽  
Chromatic Dispersion ◽  
Optical Filter ◽  
Single Mode ◽  
Digital Data ◽  
Frequency Range ◽  
Optical Source ◽  
Multimode Laser ◽  
Microwave Photonic ◽  
Birefringent Optical Fiber

In this paper, we have demonstrated a duplex microwave photonic filter system. The reconfigurability of a microwave passband filter by using a birefringent optical filter has also been demonstrated experimentally. The effect of filtering normally depends on the intermodal separation of a multimode laser diode (MLD), as well as the chromatic dispersion parameter and the length of a Single Mode-Standard Fiber (SM-SF). However, in this work, the intermodal separation of the MLD is altered by an optical filter which consists of a section of birefringent optical fiber (BOF) placed between crossed polarizers. Using this filter, six passbands in the frequency range of 0–10 GHz are obtained. Our duplex Microwave Photonic Filter (MPF) system is driven by only a single optical source. Performance evaluation for the filtered passband is also given in terms of the Signal-to-Noise-Ratio (SNR). On average, an SNR of 13.87 dB is obtained for all the passbands generated by our duplex Microwave Photonic Filter (MPF) system. For potential applications, the generated passbands may be used as radio frequency (RF) carriers to transmit analog or digital data in an optical communications system.

scholarly journals Experimental Transmission of Digital Data Coded on Electrical Carriers at 2.1 GHz and 4.2 GHz by Using a Microwave Photonic Filter

Electronics ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 833
Author(s):  
Ana Gabriela Correa-Mena ◽  
Alicia Vera-Marquina ◽  
Alejandro García-Juárez ◽  
Jorge Rodríguez-Asomoza ◽  
Ignacio Enrique Zaldívar-Huerta
Keyword(s):  
Signal Transmission ◽  
Single Mode ◽  
Passive Optical Network ◽  
Digital Data ◽  
Digital Signals ◽  
High Definition ◽  
Microwave Band ◽  
Multimode Laser ◽  
Microwave Photonic ◽  
Band Pass

This paper proposes and demonstrates the use of filtered microwave band-pass windows situated at 2.1 GHz and 4.2 GHz as electrical carriers to transmit digital signals. The use of an appropriate microwave photonic filter (MPF) allows for the generation of the microwave band-pass windows. The key parameters of the filtering effect are the intermodal separation of a multimode laser diode (MLD), the chromatic dispersion parameter of the optical link, and its own length. Experimentally, it is demonstrated that the filtered band-pass windows can be used as electrical carriers to transmit digital signals at frequencies of 50 MHz, 100 MHz, and 150 MHz over 25.31 km of single-mode-standard-fiber (SM-SF). The quality Q-factor, jitter, and bit-error-rate are the parameters that allow for the evaluation of the quality of the digital signal transmission. The obtained results allow for the proposition of this photonic architecture in a passive optical network (PON) to distribute services like Internet Protocol (IP) telephony, internet, streaming video, and high definition television.

scholarly journals Investigation of a selectable multi-passband microwave photonic filter based on cascaded optical comb filters

2021 ◽  
Vol 51 (3) ◽  
Author(s):  
F. Wang ◽  
M.M. Peng
Keyword(s):  
Sidelobe Suppression ◽  
Frequency Range ◽  
Optical Source ◽  
Microwave Photonic ◽  
Comb Filters ◽  
Lyot Filter ◽  
In Series ◽  
Polarization States ◽  
Fiber Filter

A multi-passband microwave photonic filter (MPF) with selectable passband frequency, spanning 0–20 GHz frequency range, is proposed, and experimentally demonstrated, in which passband frequency can be flexibly selected within a maximum passband number to four. The scheme is based on the generation of tunable optical comb lines using a broadband optical source sliced by cascaded optical comb filters, achieved by connecting an in-line birefringence fiber filter and a reconfigurable Lyot filter in series, such that various filter tap spacing and spectral combinations are obtained for the configuration of the MPF. The proposed MPF can operate with four different passband states, namely, single-, dual-, triple-, and quadruple-passband, only by adjusting polarization states of the cascaded optical comb filters. All these passbands are with a 3-dB bandwidth varying from 200 to 460 MHz and more than 20-dB sidelobe suppression.

A comparative study on the cold type and thermal type field emission guns used in the same electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 58-59
Author(s):  
M. Iwatsuki ◽  
Y. Kokubo ◽  
Y. Harada
Keyword(s):  
Electron Microscope ◽  
Field Emission ◽  
Signal To Noise Ratio ◽  
Electron Source ◽  
Resolving Power ◽  
Optical Source ◽  
Experimental Conditions ◽  
High Brightness ◽  
Illumination System ◽  
Transmission Electron

On accout of its high brightness, small optical source size, and minimal energy spread, the field emission gun (FEG) has the advantage that it provides the conventional transmission electron microscope (TEM) with a highly coherent illumination system and directly improves the resolving power and signal-to-noise ratio of the scanning electron microscope (SEM). The FEG is generally classified into two types; the cold field emission (C-FEG) and thermal field emission gun (T-FEG). The former, in which a field emitter is used at the room temperature, was successfully developed as an electron source for the SEM. The latter, in which the emitter is heated to the temperature range of 1000-1800°K, was also proved to be very suited as an electron source for the TEM, as well as for the SEM. Some characteristics of the two types of the FEG have been studied and reported by many authors. However, the results of the respective types have been obtained separately under different experimental conditions.

Performance and Reliability of a MEMS-based tunable optical filter operating in the 1565 nm-1525 nm wavelength range

2002 ◽  
Vol 722 ◽  
Author(s):  
T. S. Sriram ◽  
B. Strauss ◽  
S. Pappas ◽  
A. Baliga ◽  
A. Jean ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Line Width ◽  
Insertion Loss ◽  
Optical Filter ◽  
Single Mode ◽  
Single Mode Fiber ◽  
Reliability Testing ◽  
Silicon Nitride Membrane ◽  
Tunable Optical Filter ◽  
Extensive Performance

AbstractThis paper describes the results of extensive performance and reliability characterization of a silicon-based surface micro-machined tunable optical filter. The device comprises a high-finesse Fabry-Perot etalon with one flat and one curved dielectric mirror. The curved mirror is mounted on an electrostatically actuated silicon nitride membrane tethered to the substrate using silicon nitride posts. A voltage applied to the membrane allows the device to be tuned by adjusting the length of the cavity. The device is coupled optically to an input and an output single mode fiber inside a hermetic package. Extensive performance characterization (over operating temperature range) was performed on the packaged device. Parameters characterized included tuning characteristics, insertion loss, filter line-width and side mode suppression ratio. Reliability testing was performed by subjecting the MEMS structure to a very large number of actuations at an elevated temperature both inside the package and on a test board. The MEMS structure was found to be extremely robust, running trillions of actuations without failures. Package level reliability testing conforming to Telcordia standards indicated that key device parameters including insertion loss, filter line-width and tuning characteristics did not change measurably over the duration of the test.

scholarly journals Detection and localization of multiple small damages in beam

2021 ◽  
Vol 13 (1) ◽  
pp. 168781402098732
Author(s):  
Ayisha Nayyar ◽  
Ummul Baneen ◽  
Syed Abbas Zilqurnain Naqvi ◽  
Muhammad Ahsan
Keyword(s):  
Frequency Response ◽  
Natural Frequencies ◽  
Signal To Noise Ratio ◽  
Moving Average ◽  
A Priori ◽  
Damage Index ◽  
High Signal ◽  
Frequency Range ◽  
Spatial Locality ◽  
System Frequency

Localizing small damages often requires sensors be mounted in the proximity of damage to obtain high Signal-to-Noise Ratio in system frequency response to input excitation. The proximity requirement limits the applicability of existing schemes for low-severity damage detection as an estimate of damage location may not be known  a priori. In this work it is shown that spatial locality is not a fundamental impediment; multiple small damages can still be detected with high accuracy provided that the frequency range beyond the first five natural frequencies is utilized in the Frequency response functions (FRF) curvature method. The proposed method presented in this paper applies sensitivity analysis to systematically unearth frequency ranges capable of elevating damage index peak at correct damage locations. It is a baseline-free method that employs a smoothing polynomial to emulate reference curvatures for the undamaged structure. Numerical simulation of steel-beam shows that small multiple damages of severity as low as 5% can be reliably detected by including frequency range covering 5–10th natural frequencies. The efficacy of the scheme is also experimentally validated for the same beam. It is also found that a simple noise filtration scheme such as a Gaussian moving average filter can adequately remove false peaks from the damage index profile.

Joint Encryption and Compression-Based Watermarking Technique for Security of Digital Documents

2021 ◽  
Vol 21 (1) ◽  
pp. 1-20
Author(s):  
A. K. Singh ◽  
S. Thakur ◽  
Alireza Jolfaei ◽  
Gautam Srivastava ◽  
MD. Elhoseny ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Similarity Index ◽  
Structural Similarity ◽  
Digital Data ◽  
The Internet ◽  
Discrete Wavelet ◽  
Compression Performance ◽  
Strong Compression ◽  
Multiple Watermarks ◽  
Value Decomposition

Recently, due to the increase in popularity of the Internet, the problem of digital data security over the Internet is increasing at a phenomenal rate. Watermarking is used for various notable applications to secure digital data from unauthorized individuals. To achieve this, in this article, we propose a joint encryption then-compression based watermarking technique for digital document security. This technique offers a tool for confidentiality, copyright protection, and strong compression performance of the system. The proposed method involves three major steps as follows: (1) embedding of multiple watermarks through non-sub-sampled contourlet transform, redundant discrete wavelet transform, and singular value decomposition; (2) encryption and compression via SHA-256 and Lempel Ziv Welch (LZW), respectively; and (3) extraction/recovery of multiple watermarks from the possibly distorted cover image. The performance estimations are carried out on various images at different attacks, and the efficiency of the system is determined in terms of peak signal-to-noise ratio (PSNR) and normalized correlation (NC), structural similarity index measure (SSIM), number of changing pixel rate (NPCR), unified averaged changed intensity (UACI), and compression ratio (CR). Furthermore, the comparative analysis of the proposed system with similar schemes indicates its superiority to them.

Study of Wireless Torque Measurement System Based on CC2500

2011 ◽  
Vol 383-390 ◽  
pp. 5300-5303
Author(s):  
Wei Liu ◽  
Xiao Jie Song ◽  
Wen Gang Chen
Keyword(s):  
Signal To Noise Ratio ◽  
Digital Data ◽  
Measuring System ◽  
Instrumentation Amplifier ◽  
Torque Sensor ◽  
Torque Measurement ◽  
Analog To Digital ◽  
Wireless Transceiver ◽  
Precision Measuring ◽  
Transmission Shaft

It’s very difficult to get high precision measuring result using contact torquemeter because of very low signal-to-noise ratio. To overcome this defect, a wireless torque measuring system is designed based on CC2500. This system uses strain gauge torque sensor to measure the surface principal stress of the transmission shaft, and get the maximum shearing stress, and then the torque that the transmission shaft bears. The weak output signal of torque sensor is magnified by the instrumentation amplifier AD623, and sent to the analog-to-digital convertor. These digital data are transmited to the portable receiving terminal by the wireless transceiver chip CC2500. The dynamic wireless torque measurement is realized by this system.

Sign in / Sign up

Export Citation Format

Share Document