China
Africa
Explore chapters and articles related to this topic
Coherent Optical Receiver
Published in Le Nguyen Binh, Optical Modulation, 2017
Detailed analyses of amplifier noises and their equivalent noise sources, referred to input ports, are given in the Annex 2 of Reference 33. It is noted that noises have no flowing direction as they always add and no substraction, thus the noises are measured as noise power and not as a current. Electrical spectrum analyzers are commonly used to measured the total noise spectral density, or the distribution of noise voltages over the spectral range under consideration, which is defined as the noise power spectral density distribution.
Optical Coherent Detection and Processing Systems
Published in Le Nguyen Binh, Advanced Digital, 2017
Detailed analyses of amplifier noise and the equivalent noise sources as referred to input ports are given in Annex 2. It is noted that noise has no direction of flow as they always add and do not subtract, and thus noise is measured as noise power and not as current. Thus, electrical spectrum analyzers are commonly used to measure the total noise spectral density, or the distribution of noise voltage over the spectral range under consideration, which is thus defined as the noise power spectral density distribution.
Noise and sensitivity comparison for different BP filter designs
Published in Automatika, 2021
Zoran Šverko, Nino Stojković, Saša Vlahinić, Ivan Markovinović
Voltage noise spectral density is calculated using Equation (7). Figure 11 shows the total voltage noise spectral density. Using theoretical values based on thermal noise sources in calculations by MATLAB and real elements noise models by SPICE, we can ascertain the distinction between calculated and simulated values. The noise components for both sections are shown in Figure 11(b,c). In this design, LT1228 was used as a transconductance amplifier. The mentioned transconductance amplifier has the input voltage noise source of En= 6 nV/√ Hz and the input current noise source In= 1.4 pA/√ Hz. Considering these facts, the current noise source is much lower than the voltage noise source, and for this reason it was neglected in the calculation.
A bulk-driven, buffer-biased, gain-boosted amplifier for biomedical signal enhancement
Published in Cogent Engineering, 2019
Sarin Vijay Mythry, D. Jackuline Moni
In order to design low noise amplifier for biomedical applications, transistor size and biasing are the most important parameters. To estimate the RMS noise of an amplifier, integration of bio-amplifier noise spectral density along with bandwidth is essential. Due to large time constants of integration limits, Rf and Cf in should be considered to be close to zero. The noise displayed at the output of an amplifier is measured as a voltage. The noise is mainly produced by both current and voltage sources. The most widely used specifications for amplifier circuit noise are the IR current and IR voltage noise. These are called IR spectral density function or also called as RMS noise. The V/√Hz is required because of noise power which is added with bandwidth (Hz) or current and voltage noise density will be added with √Hz. The high gain amplifier exhibited only at 1 Hz and still less noise of at 200 Hz. Different noise analyses are depicted in Figure 13, 22, and 23. Figure 22 depicts the squared output noise characteristics of bulk-driven gain-boosted amplifier for biomedical applications. Figure 23 depicts the equivalent output noise characteristics of bulk-driven gain-boosted amplifier for biomedical applications.
SSO Based Energy Efficient Power Allocation with Optimal Power Constraints for Underlay Cognitive Radio Networks
Published in International Journal of Electronics, 2022
Let us consider the underlay CRN as shown in Figure 1. It contains the single PUs pairs and three SUs pairs. In underlay, all users sharing a similar frequency band. Assume that the number of SUs transmitter to the quantity of SUs receivers at power level . Each user contains one transmitter and receiver. In an underlay way, SUs generate the interference to PUs that do not exceed the highest IT level and use the same frequency band licenced to PUs. The number of channels is considered. By a single pair of PU, every channel is occupied and it uses just one channel. At the same time period, SUs speculatively transfers the data for numerous channels. The pair of SUs are denoted by . The allocated transmit power of SU pair to the channel is represented by . The amount of SUs transmit power is defined by . Noise spectral density and bandwidth is characterised by and , individually. For the channel, the channel gain amongst the transmitter and receiver contains both distance and multipath fading-based channel gain. It designated as where is relate the transmitter and receiver of PU while and is parallel to SU transmitter and receiver.