1) The document discusses the modulation techniques used in various Global Navigation Satellite Systems (GNSS), including GPS, Glonass, BeiDou, and Galileo.
2) GPS uses BPSK-R modulation with a 2.046 MHz bandwidth. Glonass uses FDMA, while the others use CDMA.
3) BOC modulation, used in Galileo, modulates the signal with a subcarrier signal that can be either sine or cosine. This results in a spectral distribution around the subcarrier frequency.
GPS sensitivity questions and its HW RF considerationPei-Che Chang
1) The document discusses GPS sensitivity and RF hardware considerations. It provides equations for calculating sensitivity for different wireless technologies like GSM, CDMA, WCDMA, etc. based on factors like bandwidth, carrier-to-noise ratio, and receiver noise figure.
2) It explains the difference between carrier-to-noise ratio (CNR) which is in the RF domain versus signal-to-noise ratio (SNR) which is in the baseband domain. It also discusses the difference between carrier-to-noise ratio (C/N) and carrier-to-noise density ratio (C/N0) used in GPS sensitivity calculations.
3) Examples are provided to calculate pre- and post
The document discusses receiver architecture and design requirements. It covers:
1. The receiver must provide high gain of 100dB while spread across RF, IF, and baseband stages to avoid instability. It must also be sensitive to weak signals down to -110dBm and reject strong adjacent channels.
2. A superheterodyne receiver is most common as it allows for sharper filters at IF to improve selectivity. Downconverting to IF also eases image filtering requirements.
3. Automatic gain control is needed to adjust the receiver gain over a wide range of input signal levels and fit them into the baseband processing range. It helps prevent compression from strong signals exceeding the 1dB compression point.
OXX B66 Rx sensitivity and desense analysis issue debugPei-Che Chang
This document discusses OXX B66 Rx sensitivity analysis. It calculates the sensitivity for different B66 Rx configurations, including bypassing the external LNA and connecting directly to the mLNA or iLNA. It is determined that connecting to the mLNA yields better sensitivity due to the iLNA's higher noise figure degrading the cascade NF. The document also analyzes desense from Tx leakage into the Rx band and compares to a reference design from another company.
1. WCDMA uses BPSK in the uplink and QPSK in the downlink. Pulse shaping uses RRC (Root-Raised-Cosine) to prevent inter-symbol interference caused by group delay variations during wireless transmission.
2. Pulse shaping is introduced to eliminate noise and facilitate demodulation. WCDMA uses the RRC filter, whose time domain shape is the famous Broadcom logo sinc function.
3. LTE uses SC-FDMA in the uplink and OFDMA in the downlink. OFDM more efficiently uses bandwidth and can accommodate more users. Each OFDM sub-carrier is the Broadcom logo sinc function, with all sub-carriers being orthogonal called
1. The document discusses GPS signal power received on Earth from satellites in low Earth orbit. It calculates the free space path loss over the 20,000 km distance to be approximately 180.4 dB.
2. GPS satellites transmit signals at 25.6 Watts with a 13 dBi antenna gain, resulting in an effective isotropic radiated power of around 500 Watts or 27 dBW.
3. Accounting for the 180.4 dB free space path loss and 2 dB of atmospheric loss, the received power at the Earth's surface is calculated to be -155 dBW, which has a 5 dB margin above the specification of -160 dBW.
1) The document discusses the modulation techniques used in various Global Navigation Satellite Systems (GNSS), including GPS, Glonass, BeiDou, and Galileo.
2) GPS uses BPSK-R modulation with a 2.046 MHz bandwidth. Glonass uses FDMA, while the others use CDMA.
3) BOC modulation, used in Galileo, modulates the signal with a subcarrier signal that can be either sine or cosine. This results in a spectral distribution around the subcarrier frequency.
GPS sensitivity questions and its HW RF considerationPei-Che Chang
1) The document discusses GPS sensitivity and RF hardware considerations. It provides equations for calculating sensitivity for different wireless technologies like GSM, CDMA, WCDMA, etc. based on factors like bandwidth, carrier-to-noise ratio, and receiver noise figure.
2) It explains the difference between carrier-to-noise ratio (CNR) which is in the RF domain versus signal-to-noise ratio (SNR) which is in the baseband domain. It also discusses the difference between carrier-to-noise ratio (C/N) and carrier-to-noise density ratio (C/N0) used in GPS sensitivity calculations.
3) Examples are provided to calculate pre- and post
The document discusses receiver architecture and design requirements. It covers:
1. The receiver must provide high gain of 100dB while spread across RF, IF, and baseband stages to avoid instability. It must also be sensitive to weak signals down to -110dBm and reject strong adjacent channels.
2. A superheterodyne receiver is most common as it allows for sharper filters at IF to improve selectivity. Downconverting to IF also eases image filtering requirements.
3. Automatic gain control is needed to adjust the receiver gain over a wide range of input signal levels and fit them into the baseband processing range. It helps prevent compression from strong signals exceeding the 1dB compression point.
OXX B66 Rx sensitivity and desense analysis issue debugPei-Che Chang
This document discusses OXX B66 Rx sensitivity analysis. It calculates the sensitivity for different B66 Rx configurations, including bypassing the external LNA and connecting directly to the mLNA or iLNA. It is determined that connecting to the mLNA yields better sensitivity due to the iLNA's higher noise figure degrading the cascade NF. The document also analyzes desense from Tx leakage into the Rx band and compares to a reference design from another company.
1. WCDMA uses BPSK in the uplink and QPSK in the downlink. Pulse shaping uses RRC (Root-Raised-Cosine) to prevent inter-symbol interference caused by group delay variations during wireless transmission.
2. Pulse shaping is introduced to eliminate noise and facilitate demodulation. WCDMA uses the RRC filter, whose time domain shape is the famous Broadcom logo sinc function.
3. LTE uses SC-FDMA in the uplink and OFDMA in the downlink. OFDM more efficiently uses bandwidth and can accommodate more users. Each OFDM sub-carrier is the Broadcom logo sinc function, with all sub-carriers being orthogonal called
1. The document discusses GPS signal power received on Earth from satellites in low Earth orbit. It calculates the free space path loss over the 20,000 km distance to be approximately 180.4 dB.
2. GPS satellites transmit signals at 25.6 Watts with a 13 dBi antenna gain, resulting in an effective isotropic radiated power of around 500 Watts or 27 dBW.
3. Accounting for the 180.4 dB free space path loss and 2 dB of atmospheric loss, the received power at the Earth's surface is calculated to be -155 dBW, which has a 5 dB margin above the specification of -160 dBW.
1) Heterodyne receivers down-convert high frequency RF signals to a lower intermediate frequency (IF) by mixing the RF signal with a local oscillator (LO) signal. This allows for easier filtering and selection of the desired channel.
2) However, heterodyne receivers suffer from image interference, where signals at RF ± LO are both down-converted to the IF. Additional filtering is needed to suppress the unwanted image signal.
3) Dual-IF receivers implement two down-conversion stages to simultaneously achieve good image rejection and channel selection. However, additional issues like mixing spurs arise due to harmonics of the LO signals. Most receivers therefore use a single IF architecture.
The document discusses various impairments that can affect error vector magnitude (EVM) testing, including thermal noise, phase noise, spurious signals, amplitude and phase non-linearities, filtering effects, DC offsets, and IQ mismatches. It emphasizes that designing an accurate EVM test bench requires a low internal EVM and minimizing these impairments through calibration. Presto Engineering is an experienced test house for evaluating EVM, especially at millimeter wave frequencies.
A Study On TX Leakage In 4G LTE Handset Terminalscriterion123
The document discusses duplexing and its impact on receiver sensitivity in cellular phones. It describes how frequency division duplexing uses separate sub-bands for simultaneous transmission and reception. Duplex filters are needed to separate the transmit and receive frequencies and prevent transmitter noise and power from desensitizing the receiver. Issues like poor duplexer isolation, non-50 ohm impedances, and improper layout can all allow transmit signal leakage and interference with the receiver sensitivity.
Performance Requirement and Lessons Learnt of LTE Terminal_Transmitter Partcriterion123
1. The document discusses transmitter output power specifications for LTE and WCDMA, including maximum output power levels and tolerances.
2. It provides lessons learned from issues with output power, EVM, and other signal quality metrics on various device bands. Common causes included improper gain mode selection, impedance mismatches, and oscillator pulling from strong RF signals.
3. Key recommendations include separating PA and transceiver shielding areas, compensating output power for temperature and frequency variations, avoiding routing near noise sources, and using proper gain/loss configurations.
1. This document discusses various analog modulation techniques used to transmit digital data, including ASK, FSK, PSK, and QAM.
2. It provides examples and explanations of how each technique works, such as varying the amplitude (ASK), frequency (FSK), or phase (PSK) of a carrier signal to represent the 1s and 0s of digital data.
3. QAM is described as a technique that modulates signals onto both the cosine (in-phase) and sine (quadrature-phase) components of a carrier, allowing it to encode multiple bits per symbol.
The ABCs of ADCs Understanding How ADC Errors Affect System Performancecriterion123
Dynamic range is an important consideration for digital receivers. A high dynamic range allows a receiver to capture both weak and strong signals. Digital variable gain amplifiers provide gain adjustment to keep signal levels constant at the analog-to-digital converter (ADC) input. Factors like modulation type, noise, distortion, and peak-to-average power ratio determine the required ADC dynamic range. Proper automatic gain control and oversampling can help improve dynamic range performance.
This document discusses several issues related to transmitter timing and power amplifier settings in cellular devices. It notes that rich spurs have been observed in the 500-700MHz range during conducted spurious emission measurements, even across different channels and power control levels. Improper timing of power amplifier enable signals can also affect the maximum transmit power and calibration of certain bands. The timing of power amplifier on and range signals must be set correctly to avoid lower than expected output power or failures in band calibration. References are provided from Qualcomm and Slideshare documents discussing transmitter spur and GSM open-loop power control issues.
Sensitivity or selectivity - How does eLNA impact the receriver performancecriterion123
it describes
1. Why need external LNA ?
2. Why does poor linearity lead to poor sensitivity ?
3. For the eLNA gain, the more the better ?
4. Why can SAW filter improve linearity ?
RF Module Design - [Chapter 5] Low Noise AmplifierSimen Li
This document discusses low noise amplifier design. It begins with an outline and introduction. It then covers basic amplifier configurations like common-emitter, common-base, and common-collector. It discusses the cascode low noise amplifier configuration and how it improves frequency response and isolation. Feedback topologies like series and shunt feedback are also covered. The document provides explanations of noise figure, input matching, and how bias current affects noise. Design techniques like inductive input matching and the effect of Miller capacitance on matching are summarized.
This document provides an overview of fundamentals of RF systems. It discusses topics such as microwave transmission, modulation, antennas, transmission lines, amplifiers, and filters. Key concepts covered include up-conversion and down-conversion in transmitters and receivers, characteristics of common transmission line types like coaxial cables and microstrip lines, impedance matching in amplifiers, and specifications of components like low noise amplifiers and filters. The document serves as an introduction to basic RF engineering principles.
Some issue due to incorrect PA and transceiver configurationcriterion123
1. The document discusses several power-related issues with a transceiver module. It analyzes why Band 27 can achieve minimum power levels but Band 28 cannot, finding the likely cause to be something wrong with the power amplifier (PA).
2. Another issue examined is why the transceiver passes error tests in WCDMA mode but fails in HSUPA mode. It determines the cause is probably carrier leakage from an incorrect transceiver power mode setting when transmitting at maximum power.
3. A final issue covered is lower maximum output power in online mode versus factory test mode. The document finds the feedback receiver function is not used in factory mode, and incomplete calibration of the power detection circuit likely causes abnormal
1) A phase-locked loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input signal, allowing it to synchronize signals or generate a frequency that is a multiple of the input frequency.
2) In a simple PLL, a phase detector (PD) converts the phase difference between the input and a voltage-controlled oscillator (VCO) output to a voltage, which changes the VCO frequency to follow the input.
3) Ripple in the control voltage to the VCO can produce side bands, so a low-pass filter is used to fix this voltage ripple problem and improve stability.
1 RB sensitivity at middle RBs poor than other RBsPei-Che Chang
1. Measuring LTE sensitivity with a single resource block (RB) located in the middle of the channel can degrade sensitivity. This is because control channels like the primary synchronization signal (PSS), secondary synchronization signal (SSS) and physical broadcast channel (PBCH) are also located in the middle, making decoding more difficult.
2. With a single middle RB, the coding rate needs to be twice as high on subframe 0 compared to other subframes to achieve the same block error rate. This requires at least 3dB higher signal-to-noise ratio (SNR).
3. Testing sensitivity with few RBs near the channel center can also degrade sensitivity slightly due to interference from the in-band
This document discusses selecting the type of notch filter to place at the output of a PA to reject the second harmonic frequency. It analyzes using either a series or shunt notch filter. It determines that a shunt filter is better despite having slightly lower simulated rejection. This is because the series filter actually has more insertion loss due to additional impedance discontinuities compared to the shunt filter. It also finds that adding a stub to the shunt filter reduces its rejection performance. Finally, it notes that placing the filter closer to the PA will affect the PA's load pull characteristics more.
LTE carrier aggregation technology development and deployment worldwidecriterion123
Carrier aggregation (CA) allows the combination of multiple component carriers to increase bandwidth and throughput. CA can be intra-band, combining contiguous or non-contiguous carriers within a band, or inter-band, combining carriers across frequency bands. Inter-band CA provides more flexibility to utilize fragmented spectrum. The LTE standard defines a maximum of five component carriers for CA. CA improves downlink throughput by increasing bandwidth but may not always increase uplink throughput due to limitations of UE maximum power. Close frequency band CA and FDD-TDD CA require additional RF components to separate signal paths and prevent interference between bands.
1) This document discusses different types of AM receivers including their components and characteristics. It covers AM demodulators such as envelope detectors and product detectors used to extract the audio signal from the AM carrier wave.
2) Key receiver parameters that determine performance are discussed such as selectivity, sensitivity, bandwidth improvement factor, dynamic range, fidelity and insertion loss. Selectivity refers to a receiver's ability to reject unwanted signals, while sensitivity is the minimum signal it can detect.
3) Bandwidth improvement factor reduces noise by decreasing the ratio of RF bandwidth to IF bandwidth. Dynamic range is the range between minimum and maximum usable input signals before distortion occurs.
This document discusses several common radio frequency interference (RFI) and desense issues encountered in mobile devices and potential solutions. Issues covered include DDR memory clock desense, transceiver noise coupling, switching regulator noise radiating and coupling to antennas, LCD and touchscreen driver noise, and interference from USB, HDMI and other ports radiating or coupling to antennas. Solutions proposed involve modifying clock frequencies, adding decoupling capacitors, improving shielding and isolation between components, modifying circuit board layouts, and adding EMI filters.
1) Heterodyne receivers down-convert high frequency RF signals to a lower intermediate frequency (IF) by mixing the RF signal with a local oscillator (LO) signal. This allows for easier filtering and selection of the desired channel.
2) However, heterodyne receivers suffer from image interference, where signals at RF ± LO are both down-converted to the IF. Additional filtering is needed to suppress the unwanted image signal.
3) Dual-IF receivers implement two down-conversion stages to simultaneously achieve good image rejection and channel selection. However, additional issues like mixing spurs arise due to harmonics of the LO signals. Most receivers therefore use a single IF architecture.
The document discusses various impairments that can affect error vector magnitude (EVM) testing, including thermal noise, phase noise, spurious signals, amplitude and phase non-linearities, filtering effects, DC offsets, and IQ mismatches. It emphasizes that designing an accurate EVM test bench requires a low internal EVM and minimizing these impairments through calibration. Presto Engineering is an experienced test house for evaluating EVM, especially at millimeter wave frequencies.
A Study On TX Leakage In 4G LTE Handset Terminalscriterion123
The document discusses duplexing and its impact on receiver sensitivity in cellular phones. It describes how frequency division duplexing uses separate sub-bands for simultaneous transmission and reception. Duplex filters are needed to separate the transmit and receive frequencies and prevent transmitter noise and power from desensitizing the receiver. Issues like poor duplexer isolation, non-50 ohm impedances, and improper layout can all allow transmit signal leakage and interference with the receiver sensitivity.
Performance Requirement and Lessons Learnt of LTE Terminal_Transmitter Partcriterion123
1. The document discusses transmitter output power specifications for LTE and WCDMA, including maximum output power levels and tolerances.
2. It provides lessons learned from issues with output power, EVM, and other signal quality metrics on various device bands. Common causes included improper gain mode selection, impedance mismatches, and oscillator pulling from strong RF signals.
3. Key recommendations include separating PA and transceiver shielding areas, compensating output power for temperature and frequency variations, avoiding routing near noise sources, and using proper gain/loss configurations.
1. This document discusses various analog modulation techniques used to transmit digital data, including ASK, FSK, PSK, and QAM.
2. It provides examples and explanations of how each technique works, such as varying the amplitude (ASK), frequency (FSK), or phase (PSK) of a carrier signal to represent the 1s and 0s of digital data.
3. QAM is described as a technique that modulates signals onto both the cosine (in-phase) and sine (quadrature-phase) components of a carrier, allowing it to encode multiple bits per symbol.
The ABCs of ADCs Understanding How ADC Errors Affect System Performancecriterion123
Dynamic range is an important consideration for digital receivers. A high dynamic range allows a receiver to capture both weak and strong signals. Digital variable gain amplifiers provide gain adjustment to keep signal levels constant at the analog-to-digital converter (ADC) input. Factors like modulation type, noise, distortion, and peak-to-average power ratio determine the required ADC dynamic range. Proper automatic gain control and oversampling can help improve dynamic range performance.
This document discusses several issues related to transmitter timing and power amplifier settings in cellular devices. It notes that rich spurs have been observed in the 500-700MHz range during conducted spurious emission measurements, even across different channels and power control levels. Improper timing of power amplifier enable signals can also affect the maximum transmit power and calibration of certain bands. The timing of power amplifier on and range signals must be set correctly to avoid lower than expected output power or failures in band calibration. References are provided from Qualcomm and Slideshare documents discussing transmitter spur and GSM open-loop power control issues.
Sensitivity or selectivity - How does eLNA impact the receriver performancecriterion123
it describes
1. Why need external LNA ?
2. Why does poor linearity lead to poor sensitivity ?
3. For the eLNA gain, the more the better ?
4. Why can SAW filter improve linearity ?
RF Module Design - [Chapter 5] Low Noise AmplifierSimen Li
This document discusses low noise amplifier design. It begins with an outline and introduction. It then covers basic amplifier configurations like common-emitter, common-base, and common-collector. It discusses the cascode low noise amplifier configuration and how it improves frequency response and isolation. Feedback topologies like series and shunt feedback are also covered. The document provides explanations of noise figure, input matching, and how bias current affects noise. Design techniques like inductive input matching and the effect of Miller capacitance on matching are summarized.
This document provides an overview of fundamentals of RF systems. It discusses topics such as microwave transmission, modulation, antennas, transmission lines, amplifiers, and filters. Key concepts covered include up-conversion and down-conversion in transmitters and receivers, characteristics of common transmission line types like coaxial cables and microstrip lines, impedance matching in amplifiers, and specifications of components like low noise amplifiers and filters. The document serves as an introduction to basic RF engineering principles.
Some issue due to incorrect PA and transceiver configurationcriterion123
1. The document discusses several power-related issues with a transceiver module. It analyzes why Band 27 can achieve minimum power levels but Band 28 cannot, finding the likely cause to be something wrong with the power amplifier (PA).
2. Another issue examined is why the transceiver passes error tests in WCDMA mode but fails in HSUPA mode. It determines the cause is probably carrier leakage from an incorrect transceiver power mode setting when transmitting at maximum power.
3. A final issue covered is lower maximum output power in online mode versus factory test mode. The document finds the feedback receiver function is not used in factory mode, and incomplete calibration of the power detection circuit likely causes abnormal
1) A phase-locked loop (PLL) is a control system that generates an output signal whose phase is related to the phase of an input signal, allowing it to synchronize signals or generate a frequency that is a multiple of the input frequency.
2) In a simple PLL, a phase detector (PD) converts the phase difference between the input and a voltage-controlled oscillator (VCO) output to a voltage, which changes the VCO frequency to follow the input.
3) Ripple in the control voltage to the VCO can produce side bands, so a low-pass filter is used to fix this voltage ripple problem and improve stability.
1 RB sensitivity at middle RBs poor than other RBsPei-Che Chang
1. Measuring LTE sensitivity with a single resource block (RB) located in the middle of the channel can degrade sensitivity. This is because control channels like the primary synchronization signal (PSS), secondary synchronization signal (SSS) and physical broadcast channel (PBCH) are also located in the middle, making decoding more difficult.
2. With a single middle RB, the coding rate needs to be twice as high on subframe 0 compared to other subframes to achieve the same block error rate. This requires at least 3dB higher signal-to-noise ratio (SNR).
3. Testing sensitivity with few RBs near the channel center can also degrade sensitivity slightly due to interference from the in-band
This document discusses selecting the type of notch filter to place at the output of a PA to reject the second harmonic frequency. It analyzes using either a series or shunt notch filter. It determines that a shunt filter is better despite having slightly lower simulated rejection. This is because the series filter actually has more insertion loss due to additional impedance discontinuities compared to the shunt filter. It also finds that adding a stub to the shunt filter reduces its rejection performance. Finally, it notes that placing the filter closer to the PA will affect the PA's load pull characteristics more.
LTE carrier aggregation technology development and deployment worldwidecriterion123
Carrier aggregation (CA) allows the combination of multiple component carriers to increase bandwidth and throughput. CA can be intra-band, combining contiguous or non-contiguous carriers within a band, or inter-band, combining carriers across frequency bands. Inter-band CA provides more flexibility to utilize fragmented spectrum. The LTE standard defines a maximum of five component carriers for CA. CA improves downlink throughput by increasing bandwidth but may not always increase uplink throughput due to limitations of UE maximum power. Close frequency band CA and FDD-TDD CA require additional RF components to separate signal paths and prevent interference between bands.
1) This document discusses different types of AM receivers including their components and characteristics. It covers AM demodulators such as envelope detectors and product detectors used to extract the audio signal from the AM carrier wave.
2) Key receiver parameters that determine performance are discussed such as selectivity, sensitivity, bandwidth improvement factor, dynamic range, fidelity and insertion loss. Selectivity refers to a receiver's ability to reject unwanted signals, while sensitivity is the minimum signal it can detect.
3) Bandwidth improvement factor reduces noise by decreasing the ratio of RF bandwidth to IF bandwidth. Dynamic range is the range between minimum and maximum usable input signals before distortion occurs.
This document discusses several common radio frequency interference (RFI) and desense issues encountered in mobile devices and potential solutions. Issues covered include DDR memory clock desense, transceiver noise coupling, switching regulator noise radiating and coupling to antennas, LCD and touchscreen driver noise, and interference from USB, HDMI and other ports radiating or coupling to antennas. Solutions proposed involve modifying clock frequencies, adding decoupling capacitors, improving shielding and isolation between components, modifying circuit board layouts, and adding EMI filters.
Distributed Architecture of Subspace Clustering and RelatedPei-Che Chang
Distributed Architecture of Subspace Clustering and Related
Sparse Subspace Clustering
Low-Rank Representation
Least Squares Regression
Multiview Subspace Clustering
Probabilistic Matrix Factorization (PMF)
Bayesian Probabilistic Matrix Factorization (BPMF) using
Markov Chain Monte Carlo (MCMC)
BPMF using MCMC – Overall Model
BPMF using MCMC – Gibbs Sampling
1) The document presents the Low-Rank Regularized Heterogeneous Tensor Decomposition (LRRHTD) method for subspace clustering. LRRHTD seeks orthogonal projection matrices for all but the last tensor mode, and a low-rank projection matrix imposed with nuclear norm for the last mode, to obtain the lowest rank representation that reveals global sample structure for clustering.
2) LRRHTD models an Mth-order tensor dataset as a (M+1)th-order tensor by concatenating individual samples. It aims to find M orthogonal factor matrices for intrinsic representation and the lowest rank representation using the mapped low-dimensional tensor as a dictionary.
3) LRRHTD formulates an
Brief Introduction About Topological Interference Management (TIM)Pei-Che Chang
This document discusses topological interference management (TIM) techniques for interference channels. TIM exploits interference alignment principles under realistic channel state information assumptions. The key ideas are:
- Focus on canceling strong interference links based on knowledge of the interference pattern
- There is a connection between TIM and the index coding problem
- The goal of TIM is to maximize degrees of freedom (DoF) based on network topology information
- Examples show how transmitting signals over multiple channel uses and exploiting the interference pattern can achieve different DoF values through interference alignment
This document discusses patch antennas. It describes the basic structure of a patch antenna, which consists of a radiating metallic patch on a dielectric substrate with a ground plane on the other side. Patch antennas radiate a linearly polarized wave and have a very low profile. Their primary limitation is narrow bandwidth, which is typically less than 5% for single-substrate designs. Common patch antenna geometries include rectangular and circular shapes to generate different beam patterns.
This document discusses various topics related to antenna fundamentals including:
1. It defines key antenna terminology such as radiation patterns, beamwidth, directivity, gain, polarization, and more.
2. It describes different categories of antenna types including loops, dipoles, slots, reflectors, patches, and more.
3. It covers antenna parameters and concepts such as radiation patterns, beam efficiency, radiation intensity, effective aperture, polarization, near and far field zones, and more.
This document discusses peak-to-average power ratio (PAPR) reduction techniques for orthogonal frequency-division multiplexing (OFDM) signals. It begins with an introduction to PAPR and its causes for OFDM signals. It then outlines various PAPR reduction techniques including clipping, coding, probabilistic/scrambling, predistortion, and DFT-spreading. Each technique has benefits but also cons such as distortion, reduced efficiency, or increased complexity. The document provides analysis of PAPR characteristics for different OFDM parameters and modulation schemes.
This document discusses various channel estimation techniques for OFDM systems. It describes pilot structures like block, comb and lattice types and how they are suited for different channel conditions. It also explains training symbol based channel estimation techniques like LS and MMSE. DFT-based channel estimation aims to improve performance by eliminating noise outside the channel delay. Decision directed channel estimation updates the channel coefficients without pilots by using detected signal feedback.
This document provides an introduction and overview of orthogonal frequency division multiplexing (OFDM). It discusses the limitations of single-carrier transmission at high data rates due to inter-symbol interference (ISI) and the complexity of equalizers. OFDM is presented as a solution that divides the available bandwidth into multiple orthogonal subcarriers. The key concepts of OFDM covered include cyclic prefix, orthogonality of subcarriers, modulation and demodulation, and how the cyclic prefix mitigates ISI between symbols. Bit error rate simulation of an OFDM system is also demonstrated.
- The document discusses wireless channel propagation and fading. It covers topics like large-scale fading (path loss and shadowing), small-scale fading (time-selective and frequency-selective fading), and statistical characterization of fading channels.
- Small-scale fading is caused by multipath propagation and results in rapid fluctuations in the strength of the received signal over short periods of time or travel distances. It can be time-selective or frequency-selective depending on delay spread and Doppler spread.
- Common distributions for modeling fading amplitudes are Rayleigh for non-line-of-sight environments and Rician when there is a dominant line-of-sight path. The document presents models for generating both Rayleigh and Rician fading
Deterministic MIMO Channel Capacity
• CSI is Known to the Transmitter Side
• CSI is Not Available at the Transmitter Side
Channel Capacity of Random MIMO Channels
Millimeter wave 5G antennas for smartphonesPei-Che Chang
This document describes research on millimeter-wave antennas for 5G smartphones. It discusses several antenna designs for both 60 GHz and 28 GHz applications. For 60 GHz, a 2012 design integrated a 16-element phased array directly into a printed circuit board. Later designs in 2013 and 2017 explored integrating antenna arrays with reconfigurable polarization into mobile device chassis. A 2014 design proposed a 28 GHz mesh-grid patch antenna array for 5G cellular devices, demonstrating an 11 dBi gain array integrated into a Samsung phone. The document outlines various antenna designs, simulation and measurement results to enable millimeter-wave smartphone connectivity.
This document discusses intermodulation derivation and fundamental and mth order intermodulation distortion response. It appears to be a technical document about signal processing and distortion, though some of the content is in an unrecognized language so the full details cannot be determined from the provided excerpt.
8. 203
地球 GPS衛星旋轉軌道
Doppler effect引起的角速度分量
4
4
GPS /
2
1.458 10 rad/s
11 3600 58 60 2.05
26560 km 1.458 10 3874 m/s
s
s s
d dt v
d
dt
v r
ω θ
θ π
ω
ω
−
−
=
= = ≈ ×
× + × +
= = × × =
求 衛星的角速度 和運動速度
• 一個太陽日和一個恒星日之間相差3min 55.91s在這段時間裡衛星大約運行了914 km(3874m/s*235.91s).
• 對應地球表面與衛星的最高點相應的角度近似為0.045 rad(914/20192) or 2o.
• 如果衛星接近地平線相應的角度為0.035 rad or 2o.
• 因此我們可以看出對於地球表面的固定一點在每天的同一時間裡 衛星位置大約改變2o ~ 2.6o.
9. 204
地球 GPS衛星旋轉軌道
Doppler effect引起的角速度分量
4
4
GPS /
2
1.458 10 rad/s
11 3600 58 60 2.05
26560 km 1.458 10 3874 m/s.
GPS , UE , UE Doppler , where : sin
, ,
Dop
d d d s
s
s s
d dt v
d
dt
v r
S A v v v v
ω θ
θ π
ω
ω
β
−
−
=
= = ≈ ×
× + ×
=
+
= = × × =
i
i
衛星在位置 處 在位置 處 相對 的衛星角速度 造成了 頻移 值為
根據
求 衛星的角速度 和
衛星軌道速度 取水平方
運
向最大值
得
動速度
max
6
max
8
3874 6368
pler 929 k
26560
Doppler ( UE ~ 3344 k )
1575.42 10 929
C/A code L1( 1575.42 MHz),
(
m/s 334
:
4 m/hr.
UE m/
4.881
U
kHz.
3 1
hr
) ,
0
E
s e
d
s
r d
dr
v r
v
r
f v
f f
c
×
= = ≈
× ×
= = = ≈
×
=
∴
i
角速度最大值
頻移通常都很小 除非 速度
對 調製過的頻率 最大
對一個固定的觀測
引起的
的頻移
者 來說
為
Doppler 5 kHz.≈ ±最大的 頻移
10. 205
4
4
GPS /
2
1.458 10 rad/s
11 3600 58 60 2.05
26560 km 1.458 10 3874 m/s.
GPS , UE , UE Doppler , where : sin
, ,
Dop
d d d s
s
s s
d dt v
d
dt
v r
S A v v v v
ω θ
θ π
ω
ω
β
−
−
=
= = ≈ ×
× + ×
=
+
= = × × =
i
i
衛星在位置 處 在位置 處 相對 的衛星角速度 造成了 頻移 值為
根據
求 衛星的角速度 和
衛星軌道速度 取水平方
運
向最大值
得
動速度
max
6
max
8
3874 6368
pler 929 3344 k
26560
Doppler ( UE ~ 3344 k )
1575.42 10 929
C/A code L1( 1575.42 MH
(U
m/s m/
z), : 4
h
.881 kHz.
3 10
r.
UE m
,
/
E
h
)
r
s e
d
s
r d
dr
v r
v
r
f v
f f
c
×
= = ≈
× ×
= = = ≈
×
=
∴
i
角速度最大值
頻移通常都很小 除非 速度
對 調製過的頻率 最大的頻
對一個固定的觀測者
移為
引起
來說
的
receiver , receiver UE, Doppler 5 kHz.
UE, Doppler 10 kHz.
acquisition . ? , paper ,
Doppler acqu
Doppler 5 kHz
isi
.≈ ±
±
±
i
i
在設計 時 如果 用在低速 則認定載波頻率的 頻移範圍在
如果用在高速 就要假定其 頻移的範圍在
這些值對於確定 過程的搜索頻率範圍是很重要的 因此 提到的為了覆蓋高速移動
預期中的所有 頻率範圍
最大的 頻移
tion 10 kHz , .
acquisition GPS , , C/A Doppler
receiver , C/A Doppler .
acquisit
(
ion C/A
)
±
i
i
方法覆蓋的頻率範圍必須在之 內 是這麼來的
一旦 到 信號 會立刻去測量兩個重要參數 碼的起始點和載波頻率因 頻移而變化的載波頻率
接收到的一系列數據包含多個衛星信號 每個信號具有不同 碼的不同起始點和不同的 頻率
針對某個特定的衛星信號 過程就是要找到 碼的起始 . C/A .
C/A ,
acquisition C
CWave,
/A tr
.
acking .
i
點 並利用找到的起始點展開 碼頻譜
一旦解調了 碼的頻譜 輸出信號將變成 於是便得到其載波頻率
也就是說 過程就是要獲得輸入信號的 碼的起始點位置和載波頻率然後傳遞給 過程
11. 206
6
max
8
1.023 10 929
Doppler : 3.2 Hz.
3 10
if UE , 2 3.2 6.4 Hz.
, 5
C/A co
MHz , 200 ns .
track
de ,
ing , LO
C/A code
( ) ( )
c d
dc
dc
f v
f
c
f
× ×
= = ≈
×
= × =
i
i
i
頻移很小
也高速移動
在數字化衛星信號中 如果數據用 採樣 採樣頻率 則每個採樣之間相隔 採樣時間
在 過程中 我們期望 生成信號與輸入信號未
頻率很低 所以
對齊的長度
6 6 6
100 ns .
100 ns, tracking , tracking .
C/A 977.5 ns or 1/1.023 10 , Doppler C/A 1.023 10 1.023 10 6.4 Hz.
6.4 1/ 6.4 156.3 ms,
so 100
s
× × × +
= =
i
在半個採樣時間或近似 之內
若兩個信號之間相差超過這個 將失鎖 即失去 靈敏度
碼的基波碼寬為 頻移使 碼頻率由 變成
每秒內多變化了 個週期 多變化一個周期的時間為
移動 ns , 16 ms (100 156.3/ 977.5).
16 ms , LO .
, , LO , .
tracking , LO
488.75 ns (977.5/2)
s sf T
×
>
↑ ↓ ↓ ↓
< →
i
i
i
數據長度 近似花費
高速導航需 每 選擇一批數據 以保證輸入信號與 生成碼更好的匹配
半週期內匹配輸入信號與 生成碼時間 選擇一批數據時間
當輸入信號強度與 靈敏度不成問題時 輸入信號與 生成碼時間可拓寬,
但必須 選擇一批數據時間也可拓寬 78.15 ms (156.3/2).
BB DSP !!
<但必須
調參數用的到
12. 207
QSPR Training and Troubleshooting: C/N0
Interpreting results
Check that the observed speed is reasonably close to the selected Doppler (900 m/s).
Sharp changes in velocity (i.e., large max acceleration) impact GPS performance more than a small constant
drift.
The drift in speed can be converted into an equivalent drift in frequency using the following conversion:
• 1 m/s/s = 5.25 Hz/s.
PASS PASS FAIL
13. 208
Interpreting results
Check that the observed speed is reasonably close to the selected Doppler (900 m/s).
Drift rate more problematic than steady drift.
i.e. Sharp changes in velocity (i.e., large max acceleration) impact GPS performance more than a small constant
drift.
The drift in speed can be converted into an equivalent drift in frequency using the following conversion:
• 1 m/s/s = 5.25 Hz/s.
4881
5.25
929
1 m/s/s 5.25 Hz/s
drift in speed can be converted into an equivalent drift in frequency !!
≈
∴ =
⇒
∵
換算公式是降來的