High speed noise suppression

27 July 2005 Circuit & System Protection Infrastructure Government and Parastatal (Industry)

Picked up from internal clocks by transmission lines, and radiated by USB cables acting as transmitting antennas, the problems of radiated and conducted noise are well known. These problems are compounded by the usual solution, the ferrite bead, which increasingly distorts the signal waveform as speed rises to USB2.0 (high speed mode) levels.

Murata has performed extensive development in its EMI research centres with material and winding technologies to solve these problems. That solution is high coupling and high common-mode impedance at high frequencies with Murata's wirewound common mode choke coils. Design features include 100 MHz common mode impedance of 67 to 2200 Ω, rated current from 200 to 370 mA, rated voltage 50 V d.c, DWV of 125 V d.c. and 0,3 to 1,2 Ω maximum DC resistance.

As ever, exact choice of part depends on the application and conditions but generally, Murata recommends the DLW21H series for USB lines in PCs, LVDS lines, peripherals, and small items like digital cameras. Especially for USB2.0, it suggests DLM21HN900SQ2 for data lines. Because of 'End of Packet' issues, the company does not recommend impedance values above 90 Ω. For common mode noise suppression in high speed and high-density digital equipment, the DLW21S series is a good choice. Both types are in a standard 0805 format. The DLW31S series performs similar functions in a 1206 package, but includes the higher values.

These highly-coupled choke coils are part of a large range of Murata EMI filters for almost any situation.

Further reading:

The global state of physical security
Genetec News & Events Infrastructure
Physical security has become a strategic business function, improving IT collaboration and decision-making. Moreover, interest in AI has more than doubled among users, and organisations seek flexibility to deploy workloads on-premises, in the cloud, or hybrid.

Read more...

---

Clearing the Static: The importance of cleaning in ESD control
Actum Circuit & System Protection
To prevent Electrostatic Discharge (ESD) damage to sensitive electronic assemblies and components, all production, handling, packaging, and storage must take place in an ESD-protected environment.

Read more...

---

What is your ‘real’ security posture?
BlueVision Editor's Choice Information Security Infrastructure AI & Data Analytics
Many businesses operate under the illusion that their security controls, policies, and incident response plans will hold firm when tested by cybercriminals, but does this mean you are really safe?

Read more...

---

What is your ‘real’ security posture? (Part 2)
BlueVision Editor's Choice Information Security Infrastructure
In the second part of this series of articles from BlueVision, we explore the human element: social engineering and insider threats and how red teaming can expose and remedy them.

Read more...

---

Onsite AI avoids cloud challenges
SMART Security Solutions Technews Publishing Editor's Choice Infrastructure AI & Data Analytics
Most AI programs today depend on constant cloud connections, which can be a liability for companies operating in secure or high-risk environments. That reliance exposes sensitive data to external networks, but also creates a single point of failure if connectivity drops.

Read more...

---

Short-range indoor LiDAR sensor
OPTEX Perimeter Security, Alarms & Intruder Detection Infrastructure Products & Solutions
The REDSCAN Lite RLS-1010L has been developed to provide comprehensive coverage and protect high-risk security zones and vulnerable, narrow indoor spaces that are difficult to protect with traditional sensors.

Read more...

---

Direct-to-cloud surveillance platform
Surveillance Infrastructure
Oncam has announced a forthcoming end-to-end, direct-to-cloud video platform that combines AI-enabled cameras, intelligent IoT devices, and cloud-integrated video management software to deliver smarter performance with reduced complexity.

Read more...

---

Clearing the Static: Staying grounded
Actum Circuit & System Protection
To maintain reliable electrostatic discharge control, regular testing and accurate measurement are essential, with grounding products and ESD testing equipment being vital.

Read more...

---

Software security is a team sport
Information Security Infrastructure
Building and maintaining secure software is not a one-team effort; it requires the collective strength and collaboration of security, engineering, and operations teams.

Read more...

---

Smarter protection without disruption
NewElec Pretoria Circuit & System Protection
Designed for operations still running without integrated automation, NewElec’s retrofit-friendly systems let you upgrade performance and safety without overhauling your entire network.

Read more...

---