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Target Measurements Using Radar Networks
Published in Hai Deng, Zhe Geng, Radar Networks, 2020
In (Noroozi & Sebt, 2016, 2017), the noise measurements obtained by different TX–RX pairs are modeled as mutually uncorrelated zero mean WGN with diagonal covariance matrix. However, it is pointed out in (Amiri et al., 2017a) that in practice, the measurement noise associated with each TX–RX pair depends highly on the bistatic range of the target. Therefore, in (Amiri et al., 2017a), a distance-dependent Gaussian noise model is adopted and a two-stage WLS algorithm is developed to obtain the closed-from location estimate. In the first stage, the estimation problem is formulated into a set of pseudolinear BR equations by introducing nuisance parameters (i.e. the distance between the target and the receivers), and the weighting matrix is designed to minimize the estimation error. In the second stage, a closed-form location estimate is obtained by exploiting the dependency between the BRs and the target position. Since the nuisance parameters in the first stage are estimated without considering its dependence on the target position, the algorithm proposed in (Amiri et al., 2017a) is expected to have a performance degradation when the noise power is high.
Algorithms and Performance Analysis for Narrowband Internet of Things and Broadband Long-Term Evolution Coexisting System
Published in Yulei Wu, Haojun Huang, Cheng-Xiang Wang, Yi Pan, 5G-Enabled Internet of Things, 2019
Bowen Yang, Lei Zhang, Yansha Deng, Deli Qiao, Muhammad Imran
The BER versus Eb/N0 performance of NB-IoT is shown in Figure 9.9. As can be expected, it is insensitive to the guard band. In addition, the worst and the best BER curves occur when b is equal to 1 and 20, respectively. This can be explained by Figure 9.8, that is, larger noise power results in a worse signal-to-noise ratio with fixed signal power.
Continuous Wave (CW) Radars
Published in Habibur Rahman, Fundamental Principles of Radar, 2019
The receiver in a simple homodyne CW radar is not as sensitive because of increased flicker noise, which occurs in electronic devices within the radar. The noise power produced by the flicker effect varies with frequency as 1/f. Thus the detector of the CW receiver can introduce a considerable amount of flicker noise resulting in reduced receiver sensitivity. One way to overcome the effects of flicker noise is to amplify the received signal at an intermediate frequency (IF) high enough to render the flicker noise small, and then heterodyne the signal down to lower frequencies. This is achieved by using a simple dual-antenna configuration of the CW radar system shown in Figure 6.3. The receiver of this system is called a superheterodyne receiver. Instead of the usual local oscillator, a portion of the transmitted signal is shifted in frequency by an amount equal to the IF before it is mixed with the received signal. Since the output of the mixer consists of two sidebands on either side of the carrier plus the carrier, a narrow bandpass filter is used to remove all the components except the lower sideband at f0−fIF.
An Inverter Amplifier with Resistive Feedback Current Mirror Gilbert Mixer
Published in International Journal of Electronics, 2023
Devarshi Shukla, Santosh Kumar Gupta, Vijaya Bhadauria, Rajeev Tripathi
The DC gain () depends on only in the weak inversion region (as shown in Table 1). As DIBL strongly relates to the distance between drain and source regions, is controlled by the transistor length (L). The is the thermal noise factor and is approximately 25% smaller in the weak inversion region as compared to that in the strong inversion region. At low frequencies, flicker noise is comparable to thermal noise, and both must be added in the drain current noise power spectral density generated in weak inversion.