Why to do single-tone desense test ?
What is cross modulation ?
what's the difference between cross modulation and intermodulation ?
what is triple beat ?
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 ?
desence,sensitivity calculation with and without external LNA, Noise figure calculation with and without external LNA and IIP3 calculation with and without external LNA
System(board level) noise figure analysis and optimizationcriterion123
For sensitivity, what a system (board level) RF engineer can improve is only noise figure. This document describes that the noise figure concept you should know, and how to optimize it to improve sensitivity.
Why to do single-tone desense test ?
What is cross modulation ?
what's the difference between cross modulation and intermodulation ?
what is triple beat ?
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 ?
desence,sensitivity calculation with and without external LNA, Noise figure calculation with and without external LNA and IIP3 calculation with and without external LNA
System(board level) noise figure analysis and optimizationcriterion123
For sensitivity, what a system (board level) RF engineer can improve is only noise figure. This document describes that the noise figure concept you should know, and how to optimize it to improve sensitivity.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
2. DDR Desense
DDR2 frequency of 198.4 MHz and 297.6 MHz degrade
conducted Rx sensitivity: CH246 at GSM850
and CH871 at PCS1900[1].
As shown below, change DDR2 clock frequency to 200
MHz and 300 MHz to eliminate desense[1].
2
3. DDR Desense
Of course, to change DDR2 clock frequency is merely to
change the desense channels.
Nevertheless, for these high speed CLK signal, there
will be frequency selectivity response in PCB. In other
words, the sensitivity degradation level may be
mitigated as the desense channels change.
3
4. LNA Abnormal Issue
TD-LTE B38/B39/B40 sensitivity only reaches up to -80
dBm.
At transceiver input, the issue already appears.
Transceiver
Chances are that the RX IQ signals are coupled by
noise[2].
Transceiver
BaseBand
Chip
RX IQ
Noise
4
5. LNA Abnormal Issue
The iLNA integrated in transceiver has 8 gain modes,
but the iLNA state cannot switch to the highest
gain(G0) to lower the cascade noise figure while
receiving weaker RX signal, and always stays at G2[1].
The root cause is due to incorrect connection between
transceiver and baseband chip. So, iLNA cannot switch
to the highest gain(G0).
G0 G1 G2 G3 G4 G5 G6 G7
Max Min
5
6. Desensed by LCD_PCLK
The Rx channel frequency
= 884.7 MHz = 24.576 MHz ×36,
just 36 frequency multiple of 24.576 MHz LCD_PCLK[1].
At transceiver input, the issue disappears.
6
7. Desensed by LCD_PCLK
But, changed the 0 Ω to 10 Ω/100 Ω/1 kΩ, inductor, and
bead to attenuate spur on LCD_PCLK without much
improvement[1].
Removed the 0 Ω resistor completely to disconnect
LCD_PCLK (avoid LCD_PCLK leaking), and eliminate
desense[1].
BaseBand
Chip
LCM_PCLK
0 Ohm
7
8. Desensed by LCD_PCLK
There is no GND isolation between LCD_PCLK and
VPH_PWR and CLK couples to power trace.
And, PA input via is close to VPH_PWR (also routed
under PA).
8
9. Desensed by LCD_PCLK
Thus, the path is : LCM_PCLK Noise => VPH_PWR =>
PA input => RX Trace
That’s why the issue disappears at transceiver input.
PA
VPH_PWR
LCM_PCLK Noise
Transceiver
RX Trace
The only solution is to modify the layout.
9
10. CPU LTE B5 1.6 MHz Radiated Spur Issue
There are 1.6 MHz noise when LTE is connected, which
degrades DRX TIS[1].
In general, there are two suspected 1.6 MHz noise
sources : Switching noise from PMIC and ET/APT PMIC.
As marked the green circles.
BB Chip
VREG_S1/S2/S3/S4 I/Q
TransceiverPMIC
VPH_PWR
VPH_PWR
ET/APT
PMIC
PA
Vcc
10
11. CPU LTE B5 1.6 MHz Radiated Spur Issue
Change VREG_S1/S2/S3/S4’s SMPS frequency. Test
result shows that when VREG_S2 works at 4.8 MHz, the
spur frequency interval is 4.8 MHz and if VREG_S2
works at 3.84 MHz, the spur frequency interval is
1.92/3.84 MHz[1].
So, a coarse conclusion is that VREG_S2 is the
noise source[1].
PMIC
BB Chip
DRX ANT
Because VREG_S2 is between Baseband chip and PMIC,
both the shielding can are the suspected radiators
due to cavity resonator mechanism.
11
12. CPU LTE B5 1.6 MHz Radiated Spur Issue
After adding a 82 pF capacitor on VREG_S2 to filter the
in-band noise, the DRx TIS improves ~ 6 dB[1].
BB Chip
VREG_S2
PMIC
82 pF
12
13. TIS Desensed by PMIC 1.6 MHz Switch Noise
Conducted sensitivity is ok, but GSM850/900 OTA
sensitivity is ~ 6‒7 dB degraded at channel:
1.6 MHz ×X, e.g.,: 870.4 MHz = 544 ×1.6 MHz,
872 MHz = 545 ×1.6 MHz, etc.[1].
13
14. TIS Desensed by PMIC 1.6 MHz Switch Noise
It means the issue is NOT due to layout because
conducted sensitivity is okay[1].
As mentioned earlier, there are two suspected 1.6 MHz
noise sources : Switching noise from PMIC and ET/APT
PMIC.
14
15. TIS Desensed by PMIC 1.6 MHz Switch Noise
PMIC and transceiver share the same shielding can, the
1.6 MHz noise easily couples without a separate
shielding[1].
15
16. TIS Desensed by PMIC 1.6 MHz Switch Noise
Nevertheless, because conducted sensitivity is okay, it
means that the issue is NOT due to coupling
mechanism in the common shielding can.
While in PWM mode, the SMPS frequency is 1.6 MHz.
The dominant mode of desense is the 1.6 MHz pulse
train from ~ 700–900 MHz which are then picked up by
the antenna due to cavity resonator mechanism[1].
PMIC
ANT
1.6 MHz switching Noise
16
17. TIS Desensed by PMIC 1.6 MHz Switch Noise
Placing PRX/DRX ANT far away from PMIC and
separated shielding helped to avoid the switching noise
coupling to ANT[1].
17
18. Desensed by BL 1.2 MHz Switch Noise
For conductive test, some PCBs has desense issue, but
some do NOT.
Transceiver
Backlight
Driver IC
Switching Noise
Transceiver
Backlight
Driver IC
Switching Noise
For bad boards, there is aperture between transceiver
and BL driver IC, which makes shielding effect and
grounding poor. So, the switching noise leaks to
transceiver through the aperture.
Aperture
18
19. Desensed by BL 1.2 MHz Switch Noise
As shown below, with aperture, the noise floor arises.
Transceiver
Backlight
Driver IC
Consequently, the transceiver and BL driver IC should
NOT share the same shielding can.
19
20. GSM HB Rx Desensed by USB 3.0 Port
GSM HB Rx radiated test shows it was desensed on
frequency 1843.2 MHz. USB 3.0 port is close to antenna
and the USB port radiates 19.2 MHz 96th harmonics.
(19.2 MHz * 96 = 1843.2 MHz)[1].
A hardware solution is to add a bypass capacitor(15 pF)
on USB 3.0 port to improve the desense[1].
ANT
USB 3.0 CLK Noise
USB 3.0 Connector
20
21. GSM900 Radiative Sensitivity Degrade When LCD is On
Desense happens on full bands, but it is worse on the
low channel side. The peak value is CH1000 = 930.2
MHz[1].
In general, LCD panel (including driver circuit)
generates wideband noise when LCD is on; MIPI DSI
CLK and backlight driver switching noise generate
numerous narrowband spurs[1].
21
22. GSM900 Radiative Sensitivity Degrade When LCD is On
Thus, there are four ways to improve LCD On desense
issue :
MIPI DSI CLK
LCD Power supply
Backlight Driver IC
LCD FPC Grounding
22
23. GSM900 Radiative Sensitivity Degrade When LCD is On
As shown below, for LCD power, the two 10 uF
decoupling capacitors should be close to PMIC. And
(240R + 4.7 uF + 100 pF) should be close to B-to-B
connector because this combination is filter.
PMIC VREG_DISP_5V
B-to-B Connector
PMIC
10 uF 10 uF
240 R
4.7 uF 100 pF
To LCM
23
24. GSM900 Radiative Sensitivity Degrade When LCD is On
As shown below, this filter has at least 90 dB rejection
in LB range. Even though anti-resonance frequency and
HB range, the rejection is at least 70 dB.
4.7 uF 100 pF
To LCM
240 R
In general, the desense issue due to power supply
occurs in LB range (700MHz ~ 900MHz).
Thus, this filter should focus on LB
noise suppression.
24
25. GSM900 Radiative Sensitivity Degrade When LCD is On
The backlight driver IC is as shown below[3]. For PWM
pin, reserve 100 pF ; for LED 1 and LED 2, reserve (100
pF + 1uF). Do NOT put 1uF capacitor on PWM pin, or
the waveform distorts.
These filters should be close to B-to-B connector.
1uF100 pF
100 pF
25
26. GSM900 Radiative Sensitivity Degrade When LCD is On
For LX pin, reserve (240 R + 0.47 uF + 100 pF), which
should be close to B-to-B connector as well.
VREG_WLED_ANODE
To B-to-B connector
0.47 uF 100 pF
To LCM
240 R
26
27. GSM900 Radiative Sensitivity Degrade When LCD is On
DSI MIPI CLK can customized up to 500 MHz depending
on LCM requirement. the single DSI bus interference
frequency is usually CLK/12, which is up to
500 MHz/12 = 41.67 MHz[1].
27
28. GSM900 Radiative Sensitivity Degrade When LCD is On
Because MIPI DSI CLK is differential mode, which
generates common mode noise[4].
28
29. GSM900 Radiative Sensitivity Degrade When LCD is On
Thus, the EMI filter should have high common mode
noise suppression. In other words, we should choose
the EMI filter with high Scc21, and low Sdd21(low
insertion loss).
29
30. GSM900 Radiative Sensitivity Degrade When LCD is On
As shown below, vendor A has high Scc21 in 900 ~ 1000
MHz range than vendor B. In theory, vendor A has
higher noise suppression than vendor B.
30
31. GSM900 Radiative Sensitivity Degrade When LCD is On
Apparently, the GSM 900 desense issue is mitigated
with high Scc21 EMI filter.
Of course, to change the DSI CLK to avoid interference
falling to GSM Rx band is a solution as well[1].
31
33. GSM900 Radiative Sensitivity Degrade When LCD is On
For better shielding effect, the FPC should have
conductive silver paste. In addition, as marked red
circles, the FPC should have metal
GND pad for better grounding.
Otherwise, without these design,
the FPC may act like a
radiator, and radiates noise to
Antenna[5]. ANT
33
34. Nevertheless, cut the SD card connector, and the spur
near antenna is reduced about 12 dB.
WiFi 5G radiative Sensitivity Degrade When HDMI is On
There is WiFi 5GHz desense issue when HDMI is on.
And this is because there is 5.192 GHz (ch 40) spur near
antenna.
-87 dBm -99 dBm
34
35. With cut in SD card connector, the resonant frequency
moves away from WiFi 5 GHz. That is why the spur near
antenna is reduced.
WiFi 5G radiative Sensitivity Degrade When HDMI is On
Due to resonant cavity mechanism, the SD card
connector will act like a radiator. Thus, it radiates noise
to antenna and desense issue occurs.
WiFi 5Ghz Range
S11
Frequency
w/ Cut
w/o Cut
HDMI Noise
ANT
SD Card
Connector
35
36. Finally, modify the layout and replace these 0 ohm
resistors with ferrite bead to suppress HDMI CLK noise.
And the issue is solved.
WiFi 5G radiative Sensitivity Degrade When HDMI is On
However, to cut the SD Card connector is not a suitable
solution. After checking the layout, the HDMI CLK noise
couples to SDIO related traces due to insufficient
isolation.
SD Card
Connector
HDMI CLK trace
SDIO related trace
HDMI Noise
36
37. Reference
[1] Rx Desense Common Issue, Qualcomm
[2] DDR Desense Issue, Slideshare
[3] Dual-Channel LED Driver For Smart Phone Application, NOVATEK
[4] Noise Suppression Products/EMI Suppression Filters, Murata
[5] Antenna desense on handheld equipment Application note AN4356, STMicroelectronics
37