Radio Receiver Research Articles

Quantum scaling atomic superheterodyne receiver

Measurement sensitivity is one of the critical indicators for Rydberg atomic radio receivers. This work quantitatively studies the relationship between the atomic superheterodyne receiver’s sensitivity and the number of atoms involved in the measurement. The atom number is changed by adjusting the length of the interaction area. The results show that for the ideal case where only interaction noise is present and the RF waves are uniformly distributed, the sensitivity of the atomic superheterodyne receiver exhibits a quantum scaling: the amplitude of its output signal is proportional to the atom number, and the amplitude of its read-out noise is proportional to the square root of the atom number. Hence, its sensitivity is inversely proportional to the square root of the atom number. This work also gives a detailed discussion of the properties of transit noise in atomic receivers and the influence of some non-ideal factors on sensitivity scaling. This work is significant in the field of atom-based quantum precision measurements.

A self-biased magnetoelectric wireless power transfer receiver targeting biomedical implants

A self-biased magnetoelectric wireless power transfer receiver targeting biomedical implants

A Reconfigurable Analog Baseband for Multistandard Wireless Receivers in 22-nm CMOS

This paper presents a low noise, and high linearity reconfigurable receiver (RX) analog baseband (ABB) with tunable bandwidth (BW) and gain for multi-standard applications. The designed ABB consists of a programmable gain amplifier (PGA) and a second-order active RC low-pass filter (LPF) with cutoff frequency range from 0.7 MHz–10 MHz, whereas the gain could be tuned between 0 dB and 49 dB. The proposed ABB is implemented in 22 nm CMOS process. The post-simulation results show that the current consumption is 3.36 mA from 1 V supply and the area occupies 571×328 μm 2. The ABB achieves 42.8 dBm in-band third-order harmonic intercept point (IIP3). The spurious-free dynamic range (SFDR) and in-band total harmonic distortion (THD) is 83.2 dBc and is -83.1 dB, respectively. The input referred in-band integrated noise (IRN) is 144.8 μVrms . A digital DCOC is used to calibrate the output DC level.

Noise Generators (A Review)

Introduction. At present, noise generators (noise signal generators) have a wide range of applications. For example, such devices can be used as sources of fluctuating interference when studying the limiting sensitivity of radio receivers and amplifying devices, as signal simulators of multi-channel communication equipment, as tools for measuring non-linear distortions and frequency characteristics of radio devices using spectrum analyzers with a constant bandwidth.Aim. Review of scientific achievements in the development of noise generators and their applications.Materials and methods. The material for analysis was collected using databases of scientific publications, online resources, and websites of noise generator manufacturers. The research spanned the timeframe of 60 years.Results. Various noise generators and their characteristics, currently available on the radio equipment market, are described. The analysis of their main technical characteristics is carried out; examples of their practical application are indicated.Conclusion. Noise signal generators are widely used in scientific research and are currently produced mainly by foreign companies. Domestic companies are poorly represented in this market, with little published information available. However, positive developments in this direction have recently been observed. Domestic manufacturers are launching R&D programs to develop noise signal generators, which could reduce dependence on imported products in the future

Exploration of transferable deep learning-aided radio frequency fingerprint identification systems

Radio frequency fingerprint identification (RFFI) shows great potential as a means for authenticating wireless devices. As RFFI can be addressed as a classification problem, deep learning techniques are widely utilized in modern RFFI systems for their outstanding performance. RFFI is suitable for securing the legacy existing Internet of Things (IoT) networks since it does not require any modifications to the existing end-node hardware and communication protocols. However, most deep learning-based RFFI systems require the collection of a great number of labelled signals for training, which is time-consuming and not ideal, especially for the IoT end nodes that are already deployed and configured with long transmission intervals. Moreover, the long time required to train a neural network from scratch also limits rapid deployment on legacy IoT networks. To address the above issues, two transferable RFFI protocols are proposed in this paper leveraging the concept of transfer learning. More specifically, they rely on fine-tuning and distance metric learning, respectively, and only require only a small amount of signals from the legacy IoT network. As the dataset used for transfer is small, we propose to apply augmentation in the transfer process to generate more training signals to improve performance. A LoRa-RFFI testbed consisting of 40 commercial-off-the-shelf (COTS) LoRa IoT devices and a software-defined radio (SDR) receiver is built to experimentally evaluate the proposed approaches. The experimental results demonstrate that both the fine-tuning and distance metric learning-based RFFI approaches can be rapidly transferred to another IoT network with less than ten signals from each LoRa device. The classification accuracy is over 90%, and the augmentation technique can improve the accuracy by up to 20%.

Verification of EasyGain Settings in the Roger Remote Microphone System.

The purpose of this study was to evaluate how the EasyGain settings on a wireless receiver used with a remote microphone (RM) affected output as a function of hearing loss and receiver type. To assess the effects of the EasyGain setting on a Roger receiver, a Phonak Naida V90 superpower hearing aid (HA), two universal Roger X (02) receivers, two Roger 18 integrated receivers, and a Roger Inspiro transmitter were used. An electroacoustic evaluation was performed for five degrees of hearing loss ranging from a flat 40 to 80 dB HL, and for nine EasyGain settings from +8 to -8 dB with each Roger receiver. A three-way analysis of variance indicated significant main effects of hearing loss, receiver type and EasyGain settings, as well as their two-way interactions (p < .05). Overall, the output of the integrated receiver was 2.77 dB higher than that of the universal receiver. The change in output with 2-dB changes in EasyGain setting varied with the degree of hearing loss. For mild hearing loss (40 and 50 dB), every 2-dB change in EasyGain produced an average of 1.93 dB (SD = 0.17) change in the root-mean-square (RMS) output. For the higher degrees of hearing loss (60, 70, and 80 dB HL), the change in RMS varied depending on the range of EasyGain setting as follows: when EasyGain was > 0 dB, every 2-dB change in EasyGain setting produced an average change in RMS output of 1.32 dB (SD = 0.41); however, when EasyGain was ≤ 0 dB, every 2-dB change resulted in a mean 1.95 dB (SD = 0.16) change. The benefits of EasyGain technology on the RMS output are dependent on the interaction of the receiver type, degree of hearing loss, and EasyGain settings. The results highlight the importance of electroacoustic verification to determine appropriate settings for optimal audibility when using an RM system.

Effect of spacecraft attitude on radio wave polarization measurements for the radio Receiver instrument on Swarm-E

The characteristics of a polarized radio wave detected by an antenna onboard a spacecraft depend on the relative positions of the transmitting source and the spacecraft, the orientation of the satellite antenna with respect to the wave propagation direction, the electric field of the incident wave, and the properties of the medium traversed by the wave. Precise knowledge of the radio wave propagation direction and the receiver antenna orientation is needed for resolving the received signal properties. In this work, the focus is on the coordinated experiments between the Radio Receiver Instrument (RRI) on Swarm-E and the Natural Resources Canada Ottawa transmitter (45.4°N, 75.6°W). Three experiments, in which the RRI boresight was along the ram (13 December 2017), nadir (20 December 2017) and slew-to-target (21 December 2017) directions were selected for detailed investigations and comparisons. The deviation of the RRI boresight direction from the propagation direction of the wave vector was up to 10° in the slewed pass and varied between 0° and 180° in the two other passes. The effects of the antenna pointing direction were pronounced in the observed powers on each dipole and affected the observed (apparent) polarization characteristics. The observations were not sufficient for describing the polarization state of the original signal during one third of the RRI-ram experiment when only one dipole was receiving the signal with optimal geometry. The methods developed lay the foundation for mitigating the attitude effects to determine the true polarization characteristics of the radio wave.

Significance of Medium-Wave AM Radio Broadcasting for Enhanced Disaster Resilience in Japan: A Case Study in the Kanto Region and Fukui Using Nonpowered Hoop-Shaped Radio

On the occasion of centenary anniversary of the Great Kanto Earthquake and commencement of radio broadcasting in Japan, this study reiterates the paramount importance of medium-wave (MW) AM broadcasting in safeguarding public safety and security. Utilizing the electromagnetic principles of MW, the author has earlier developed hoop-shaped radio (HOOPRA), which is a battery-free sustainable radio receiver. This study aims to determine the maximum achievable reception distance with HOOPRA for broadcasts from public stations, such as Nihon Hoso Kyokai (NHK) JOFG (927 kHz, 5 kW) in Fukui; and NHK JOAK (594 kHz, 300 kW) and JOAB (693 kHz, 500 kW) in the Kanto region. The significance of the findings in this study is that approximately 38 million individuals in the Kanto region, residing within an 80-km radius of JOAK or JOAB, can access broadcasts using only the energy of radio waves with HOOPRA. Additionally, ∼0.4 million people in Fukui, within a 15-km radius of JOFG, can potentially be recipients of the broadcast. Given that most transmitting stations operate at 5-kW power nationwide, HOOPRA can be effectively utilized within a 15-km radius of each station. Moreover, these outcomes validate the efficacy of HOOPRA as a radio receiver and provide valuable insights into the global potential applicability of MW AM radios. Furthermore, the current investigation underscores the need to reevaluate the significance of terrestrial MW broadcasting as a vital source of emergency information, especially in the event of anticipated natural disasters, such as the predicted Nankai Trough Earthquake.

Method of correlation reception of radio light with spatial resolution and its implementation

A method for receiving ultra-wideband noise-like microwave radiation -- radio light is considered, based on the correlation reception of signals coming from spaced apart space of receiving antennas, for the purpose of further effective image formation radio-illuminated environment. A mathematical model has been developed to study the formation possible response of the receiving system and assessing the influence of signal accumulation time on its dynamicrange. One-dimensional responses of the correlation receiving system to point sources of radiation were obtained, for which radio light sources were used. An experimental model of a correlation radio light receiver was developed and physical experiments were carried out with it, confirming the results obtained during modeling, as well as the overall performance of the proposed approach.

Attentive Siamese Networks for Automatic Modulation Classification Based on Multitiming Constellation Diagrams.

Automatic modulation classification (AMC) is an essential part in a cognitive radio receiver. Benefited from the discriminative constellation characteristics among most modulations, AMC methods based on constellation diagrams usually achieve pleasant performance. However, in noncooperation communication systems, constellation diagrams expressing modulations explicitly are difficult to obtain via blind symbol timing synchronization, especially in complicated wireless channels. Therefore, this article proposes a novel constellation diagram-based AMC architecture called attentive Siamese networks (ASNs) by considering multitiming constellation diagrams (MCDs) and selecting the proper symbol timings at the feature level, which is a more robust way than the conventional signal-level symbol timing synchronization. In detail, convolutional neural networks sharing the same parameters first extract deep feature vectors for MCDs. Then, an attention inference module weights all the deep feature vectors. Finally, AMC is realized based on the weighted feature vectors. Moreover, the ASN architecture can be trained end-to-end. Comparing with the state-of-the-art methods that take diverse representations of received baseband signals as input, experimental results based on the RadioML 2018.01A dataset and non-Gaussian noise dataset demonstrate that ASN achieves a remarkable improvement, whose classification accuracy goes over 99% when the signal-to-noise ratio (SNR) > 10 dB.

Observations of plasma waves generated by charged space objects

A sampling of the environment around inert space objects has determined, which linear and nonlinear waves are created by moving space debris of all sizes. Plasma waves excited by satellites and space debris moving through the Earth's plasma in low earth orbit have been measured with in situ electric field sensors on other satellites. These orbit driven plasma waves are of interest for proximity detection of space debris and sources of electrostatic and electromagnetic noise on spacecraft. Satellites and other space objects moving through the near-earth ionosphere between 200 and 1000 km altitude become electrically charged by both electron collection and photo emission in sunlight. These hypersonic, charged objects can excite a wide range of plasma waves. Measurements with the Radio Receiver Instrument (RRI) on the Swarm-E satellite have shown that electromagnetic plasma waves from known objects can be observed out to ranges of tens of kilometers. The amplitude, spectral, and polarization changes of the RRI data are consistent with electromagnetic, compressional Alfvén waves launched by charged space objects traveling across magnetic field lines. In addition, electrostatic lower hybrid waves or nonlinear ion acoustic pinned oscillations may have been self-generated and measured on the Swarm-E satellite. It is proposed that measurements of these waves with local electric field measurements or remote electromagnetic wave scatter may be useful to design systems for the location of orbiting objects. Spatial and temporal details of spacecraft charging are key to understanding the extent of waves associated with the object motion in space plasmas.

Using Software-Defined radio receivers for determining the coordinates of low-visible aerial objects

The object of this study is the process of determining the coordinates of low-visible aerial objects. The main hypothesis of the research assumed that the signals emitted by airborne systems of airborne objects that are not visible to radar stations have a greater power than the signal reflected from the airborne object. This, in turn, could improve the signal/noise ratio and, accordingly, the accuracy of determining the coordinates of low-visible aerial objects. It is suggested to use Software-Defined Radio receivers to receive such signals emitted by on-board systems of low-visible aerial objects. It was established that the main sources of signals for Software-Defined Radio receivers are signals of command, telemetry, target channels, manual control channels, and satellite navigation. It was established that an additional distinguishing feature when determining the coordinates of low-visible aerial objects is the uniqueness of their spectra and spectrograms. The method of determining the coordinates of low-visible aerial objects when using Software-Defined Radio receivers has been improved, which, unlike the known ones, involves: – the use as signals for Software-Defined Radio of signal receivers of on-board equipment of low-visible aerial objects; – the use of a priori coordinate values of a low-visible aerial object; – conducting additional spectral analysis of signals of on-board systems of low-visible aerial objects. The spectra and spectrograms of signals of on-board systems of aerial objects when using non-directional and directional antennas were experimentally determined. The experimental studies confirm the possibility of using the Software-Defined Radio receiver to receive signals from airborne equipment and improve the signal-to-noise ratio. The accuracy of determining the coordinates of aerial objects when using Software-Defined Radio receivers was evaluated. A decrease in the error of determining plane coordinates by the Software-Defined Radio system of receivers compared to the accuracy of determining coordinates by the P-19 MA radar station was established by an average of 1.88–2.47 times, depending on the distance to the aerial object

Compact high-efficiency energy harvesting positive and negative DC supplies voltage for battery-less CMOS receiver

In this paper, novel compact high-efficiency multi-band rectifiers that supply positive and negative output voltages are demonstrated for energy harvesting applications. The proposed voltage doubler circuits are used as real DC voltage supplies of radio frequency mm-wave CMOS receivers. Operating multi-band rectifiers have a complicated structure that required more resonance networks to force the rectifier to work in multi-band. Novel series and parallel resonance networks are implemented to force the rectifier to operate in dual-band at frequencies of 850 and 1400 MHz. The proposed resonance network eliminates the Schottky diode impedance variation as the input power or frequency changes and supports the impedance matching and minimizes the insertion loss. A novel high-quality sine-shape micro-strip inductor that obtains a quality factor above 65 over the frequency band from 200 to 1400 MHz and inductance equal to 14 ± 2 nH is designed to improve efficiency and enhance performance at low power levels. The first suggested RF voltage doubler rectifier with series resonance feedback between the input and cathode of the diode and parallel resonance operates at two frequency bands of 850 and 1400 MHz and obtains a peak conversion efficiency of 59%, a saturated output DC voltage is 2.5 V, and the conversion efficiency is 40% at RF-input-power of − 10 dBm. This voltage doubler achieves the required DC supply parameter (1.1 V and 450 uA) for biasing the mm-wave receiver at an RF input power of 0 dBm. Otherwise, the second suggested negative voltage rectifier has a maximum simulated conversion efficiency of 65%, saturated negative DC-voltage is − 3.5 V, and the conversion efficiency is 45% at an RF input power of − 10 dBm. The negative voltage rectifier obtains DC supply parameters (− 0.5 V and no current condition used for a gate bias) at − 10 dBm input power.

Radio Frequency Interference Measurements to Determine the New Frequency Sub-Bands of the Coaxial L-P Cryogenic Receiver of the Sardinia Radio Telescope

Radio frequency interference (RFI) represents all unwanted signals detected by radio receivers of a telescope. Unfortunately, the presence of RFI is significantly increasing with the technological development of wireless systems around the world. For this reason, RFI measurement campaigns are periodically necessary to map the RFI scenario around a telescope. The Sardinia Radio Telescope (SRT) is an Italian instrument that was designed to operate in a wide frequency band between 300 MHz and 116 GHz. One of the receivers of the telescope is a coaxial cryogenic receiver that covered a portion of the P and L bands (i.e., 305–410 MHz and 1300–1800 MHz) in its original version. Although the receiver was used for years to observe bright sources with sufficient results, its sub-bands can be redesigned considering the most recently evolved RFI scenario. In this paper, the results of a RFI measurement campaign are reported and discussed. On the basis of these results, the new sub-bands of the L-P receiver, together with the design of the new microwave filter selector block of the SRT receiver, are presented. In this way, SRT will cover up to 120 MHz and 460 MHz of −3 dB bandwidth at the P-band (290–410 MHz) and L-band (1320–1780 MHz), respectively. The bands of these filters are selected to reject the main RFI with high levels of amplitude and optimize the estimated antenna temperature and sensitivity of the receiver during the research activities, such as pulsar observations, very long baseline interferometer applications and spectroscopy science.

Adaptation of an IRAM W-Band SIS Receiver to the INAF Sardinia Radio Telescope: A Feasibility Study and Preliminary Tests.

Radio telescopes are used by astronomers to observe the naturally occurring radio waves generated by planets, interstellar molecular clouds, galaxies, and other cosmic objects. These telescopes are equipped with radio receivers that cover a portion of the radio frequency (RF) and millimetre-wave spectra. The Sardinia Radio Telescope (SRT) is an Italian instrument designed to operate between 300 MHz and 116 GHz. Currently, the SRT maximum observational frequency is 26.5 GHz. A feasibility study and preliminary tests were performed with the goal of equipping the SRT with a W-band (84-116 GHz) mono-feed radio receiver, whose results are presented in this paper. In particular, we describe the adaptation to the SRT of an 84-116 GHz cryogenic receiver developed by the Institute de Radio Astronomie Millimétrique (IRAM) for the Plateau de Bure Interferometer (PdBI) antennas. The receiver was upgraded by INAF with a new electronic control system for the remote control from the SRT control room, with a new local oscillator (LO), and with a new refrigeration system. Our feasibility study includes the design of new receiver optics. The single side band (SSB) receiver noise temperature measured in the laboratory, Trec ≈ 66 K at 86 GHz, is considered sufficiently low to carry out the characterisation of the SRT active surface and metrology system in the 3 mm band.

A Comparative Analysis of OLSR Routing Protocol based on PSO and Cuckoo Search Optimization (CSO) in Manets

New developments in wireless communication have enabled the use of highly efficient and inexpensive wireless receivers in a variety of portable applications. Each node in a mobile network is a mobile device that independently organizes its own connection to the others and manages its own data transmissions. The adaptability, scalability, and cost reduction of mobile networks have attracted considerable attention. Because mobile networks are constantly changing, problems with routing and power usage are common. High error rates, energy limitations, and inadequate bandwidth are just a few of the issues plaguing mobile ad hoc networks. The relevance of routing protocols in dynamic multi-hop networks like Mobile Ad hoc Networks (MANET) has drawn the attention of many scholars. In this paper, we focus on implementing an OLSR(Optimised Link State Routing) protocol and evaluates its performance using two optmisation algorithm: Particle Swarm Optimization(OLSR) and Cuckoo Search Optimization (CSO). The simulation result suggests that PSO is superior to both CSO and the conventional OLSR routing technique. We implemented using NS-2 simulator for simulation and NAM for network animation.

Radio frequency based distributed system for noncooperative UAV classification and positioning

With the increasing popularity of civilian unmanned aerial vehicles (UAVs), safety issues arising from unsafe operations and terrorist activities have received growing attention. To address this problem, an accurate classification and positioning system is needed. Considering that UAVs usually use radio frequency (RF) signals for video transmission, in this paper, we design a passive distributed monitoring system that can classify and locate UAVs according to their RF signals. Specifically, three passive receivers are arranged in different locations to receive RF signals. Due to the noncooperation between a UAV and receivers, it is necessary to detect whether there is a UAV signal from the received signals. Hence, convolutional neural network (CNN) is proposed to not only detect the presence of the UAV, but also classify its type. After the UAV signal is detected, the time difference of arrival (TDOA) of the UAV signal arriving at the receiver is estimated by the cross-correlation method to obtain the corresponding distance difference. Finally, the Chan algorithm is used to calculate the location of the UAV. We deploy a distributed system constructed by three software defined radio (SDR) receivers on the campus playground, and conduct extensive experiments in a real wireless environment. The experimental results have successfully validated the proposed system.

Pedestrian Positioning Using an Enhanced Ensemble Transform Kalman Filter.

Due to the unavailability of GPS indoors, various indoor pedestrian positioning approaches have been designed to estimate the position of the user leveraging sensory data measured from inertial measurement units (IMUs) and wireless signal receivers, such as pedestrian dead reckoning (PDR) and received signal strength (RSS) fingerprinting. This study is similar to the previous study in that it estimates the user position by fusing noisy positional information obtained from the PDR and RSS fingerprinting using the Bayes filter in the indoor pedestrian positioning system. However, this study differs from the previous study in that it uses an enhanced state estimation approach based on the ensemble transform Kalman filter (ETKF), called QETKF, as the Bayes filer for the indoor pedestrian positioning instead of the SKPF proposed in the previous study. The QETKF estimates the updated user position by fusing the predicted position by the PDR and the positional measurement estimated by the RSS fingerprinting scheme using the ensemble transformation, whereas the SKPF calculates the updated user position by fusing them using both the unscented transformation (UT) of UKF and the weighting method of PF. In the field of Earth science, the ETKF has been widely used to estimate the state of the atmospheric and ocean models. However, the ETKF algorithm does not consider the model error in the state prediction model; that is, it assumes a perfect model without any model errors. Hence, the error covariance estimated by the ETKF can be systematically underestimated, thereby yielding inaccurate state estimation results due to underweighted observations. The QETKF proposed in this paper is an efficient approach to implementing the ETKF applied to the indoor pedestrian localization system that should consider the model error. Unlike the ETKF, the QETKF can avoid the systematic underestimation of the error covariance by considering the model error in the state prediction model. The main goal of this study is to investigate the feasibility of the pedestrian position estimation for the QETKF in the indoor localization system that uses the PDR and RSS fingerprinting. Pedestrian positioning experiments performed using the indoor localization system implemented on the smartphone in a campus building show that the QETKF can offer more accurate positioning results than the ETKF and other ensemble-based Kalman filters (EBKFs). This indicates that the QETKF has great potential in performing better position estimation with more accurately estimated error covariances for the indoor pedestrian localization system.

Study of Automatic Gain Control System in Broadband Radio Receiver

In modern times, almost all communication systems are digital. In the receivers of such communication systems, the analog signal is discretized and quantized using an analog-to-digital converter at an intermediate frequency. Automatic gain control is used to avoid overloading the analog-to-digital converter and to maintain intermediate frequency analog signals at a suitable fixed level. If the power of the received signals is much less than the load level of the analog-to-digital converter, the automatic gain adjustment increases the gain, reducing the quantization noise. If the received signal strength is high, the automatic gain adjustment lowers the gain so that the analog-to-digital converter is not overloaded. The accuracy of the adjustment of the transmission coefficient of the automatic adjustment of the digital amplification does not always satisfy the requirements given in real time. Based on the above, the article is devoted to the study of the digital automatic gain regulator of the broadband radio receiver.

Overtaking interaction of electron-acoustic solitons in Saturn’s magnetosphere

The progression of nonlinear electron-acoustic waves (EAWs) in a magnetized and collision-free plasma made up of cold inertial electrons, inertialess superthermal electrons, and stationary background ions with special reference to Saturn’s magnetosphere (SMS) is explored. The method of reductive perturbation (MRP) is employed to obtain the evolution equation (i.e., Zakharov– Kuznetsov equation (ZKE)) that governs the propagation of electron acoustic solitons (EASs). Using the elegant and efficient Hirota bilinear method (HBM), multi-soliton solutions (MSSs) of the ZKE are determined. The impact of the effects of hot-to-cold electron density ratio, magnetic field (MF) strength, and superthermality on single as well as the interaction of EASs is examined. Estimates of the values of the electric field at several radii of SMS (i.e., 12 R s − 17.8 R s, where R s is the radius of Saturn) are presented, which are found in μV/ m to mV/ m range and are in perfect agreement with the data from Cassini radio and plasma wave science wideband receiver. Moreover, the influence of the relevant plasma parameters on the interaction time and spatial extent of the interacting EASs is also explored.