FORESIGHT NEW E-CATALOGUE VOL.19



4 Effective Approaches that Eliminate Ground Loop (Video/ Audio Interference)

What Causes Interference?

Ground loops are the major cause of interference. In an ideal electrical system, the ground potentials between the devices are zero. However, electronic devices always have different potentials as the connections get complicated. When enough current is flowing in the connection between two ground points that have different resistances, the ground loop is formed. Therefore, the noise will be produced and carried along with the signal transmitted to the receiver devices.

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Types of Grounding

Grounding plays a crucial role in electricity, so we need to figure out that before solving the problem. The ground is a reference point in an electrical circuit and is used as a reference point for voltage measurements. Generally, there're 3 types of grounds: earth ground, signal ground, and chassis ground.

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Earth Ground

It refers to the physical connection between an electrical body and the earth (typically using a metal rod fixed under the earth). When an electrical device connects to artificial or natural ground, the connection provides the path for extraneous and unwanted current to circulate through the circuit and add interference to the video/ audio signal.

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Signal Ground

Signal ground is the ground transmitted along with an analog or digital signal between electrical devices in a system. Since the devices are powered separately, they're more likely to have ground potential differences and thus produce currents to interfere. Moreover, when there're multiple paths for electricity to flow to the ground, the ground paths will carry interference currents and turn them into voltage fluctuations. This will make the ground reference in the system no longer a stable potential, and eventually, noise becomes a part of the signal.

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Chassis Ground

A chassis ground is a point that connects to the metal enclosure of an electrical device. Its use may vary by electronics manufacturers but it's typically used for shielding and grounding. By connecting the chassis with earth ground at one point, currents will be prevented from circulating through the chassis. Otherwise, the current can flow through the chassis and cause unwanted results like ground loops.

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Diagnosing

There're many reasons to cause interference. But how can we identify it is caused by ground loops? Fortunately, we can tell if it's ground loop interference by some traits, so let's look into it!

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Audio

When interference happens in an audio system, you can hear a buzz or hum sound in the background. It's annoying when it comes out in your favorite songs, but it may sound weirdly satisfying when listening to it alone, right?

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Video

In a video system, ground loops may distort picture rolling, and horizontal bars or syncing problems. The result may differ by how bad the interference is.

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Troubleshooting

When ground loops happen in different scenarios, the solutions can be different too. Following are 4 ways to respond to different applications.

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Solution #1: Have the Same Ground Reference Potential

We often see ground loop interference happen when electrical devices use different power sockets that have distinct resistances. To improve it, we recommend all A/V devices connect at the same ground point to avoid potential differences. This method is effective but too ideal to implement in some A/V systems due to complicated wiring.

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Solution #2: Separate from Metal Conductors

When AV equipment directly contacts with a metal conductor that acts as a ground point, the likelihood of getting interfered with will be greatly increased. In this case, it's recommended to place a wooden or plastic object between the equipment and the conductor to isolate the ground loop.

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Solution #3: Check All Connected Devices

Devices that interconnect in a system can make interferences as well. Try to remove the connections between all devices and replug them respectively to find the problem. Or, you can bring all equipment to another space (like a building, house). By doing so, you can check whether the interference is on the equipment. If the interference remains, try to consult an electrician to ensure that your system is properly grounded.

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Solution #4: Use Ground Loop Isolators

Sometimes, it's hard to identify what causes the ground loop, due to complicated cabling and connection. If this is the case, using a ground loop isolator can be a quick solution to the issue. It can effectively isolate the current from circulating through the circuit by cutting the loop path. It's quick, but also causes small signal loss that might compromise a little video/ audio quality.

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Warning: Remove the Ground

Removing the grounding of equipment is a misunderstanding and dangerous way to solve the issue. The main purpose of grounding is to lead the extraneous currents to the ground, avoiding surges and current leakage. If equipment is not properly grounded, the currents could flow from the conductive parts to the ground via a conductive path which can be a human body.

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How Ground Loop Isolators Work

Ground loop isolator typically uses an inductor that stores energy in a magnetic field when electric current flows through it. When the current flowing through the inductor changes, the inductor opposes any changes in current through them. Therefore, the current won't fluctuate and not lead to potential differences.

Eliminate Interference

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Types of Ground Loop Isolators

Ground loops can appear in different devices and the effect can vary. Therefore, it's important to figure out what solution is suitable for the situation and what's not. In this section, we're listing 3 major types of isolators that can solve the problem differently.

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For Video Interference

• GL001
• GL001H
• GL001HD
• GL001HDP
• TGP001
• TGP001H

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For Audio Interference

AE02GL

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For Power Interference

• GL001HP
• GL001HP-1A

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Other Causes

If you've tried everything mentioned above, maybe, the problem is not ground loops. Installation and cables can also be a major cause. Here are two things you can put your effort into.

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Improper Connections

Most of the time, signals are transmitted from one device to another via physical connections. If there is a problem with the connection, the audio and video can be also compromised. Therefore, we recommend that you check whether the cable is damaged, the connector is loose, or not matched.

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Electrical Interference between Cables

Generally, a professional A/V system has a lot of cables laying together. Because of the short distance between cables, such as power lines, telephone wires, and audio/ video cables, they have a higher likelihood of interfering with one another. In this situation, we recommend keeping at least 30cm between cables to avoid interference.

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Sum Up

We're have been in the professional A/V and CCTV industries for 20 years. From our experience, there is no one particular way that applies all circumstances. Sometimes, you have to be there to figure out what really causes the issue. This article is meant to give you a broad picture of the topic and general solutions, hope you have some takeaways from this article. If there's anything we can help with, you're welcome to give us a message!

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DP02U 4K DisplayPort KVM with USB/RS232 CAT5e Extender

• Support long reach mode distance up to 150M at 1080p@60Hz.
• Support 4K UHD at 100M.
• Audio supports up to LPCM 7.1 @ 192KHz, Dolby TrueHD, DTS-HD MA
• USB support USB 2.0 and USB 1.0 and 1.1.
• Bi-Directional RS232.

EP01HK HDBaseT/Ethernet Easy PoE Transmission Kit

• Perfect solution to send power for non-POE HDBaseT or Ethernet devices.
• To provide HDBaseT or Ethernet devices to send power over existing CAT5e/6 cable.
• Power source could be send either from EP01HI or EP01H (TX or RX) side.
• EP01HI built in isolation power to enhance power transmission reliability and safety.

2018/04/11-04/13
Booth #40905

HKM01BT-4K  4K HDMI KVM over IP/Fiber - Transmitter

HKM01BR-4K  4K HDMI KVM over IP/Fiber – Receiver

HKM01BTP-4K  With PoE function

HKM01BRP-4K  With PoE function

• Extend and distribute 4K HDMI signal with Bi-directional RS232/IR, USB and Analog Audio signals over LAN.
• Supports resolutions up to 4K@30Hz Ultra HD.
• HDCP2 compliant.
• Transmission range up to 150M over CAT5e/C
• Support 8x8 Video Wall  
• Support SFP optical transceiver, single mode distance up to 60KM.
• Built in RS232 distribution function to send RS232 signal from one TX to multiple RX.
• RS232 port support external keypad/console control ( custom made available)
• Support total of transmitter unit up to 1000 pieces, receiver unit over 60000 pieces based on the number of ports on your network switch.
• Perfect for large scale remote HD content access and security monitoring systems, digital signage applications.
• Option Model: 1U 19”Rack Mounting Panel  TPN001U: to fix one pcs HKM01BT-4K, TPN002U: to fix 2 pcs of HKM01BR-4K

VAB-12321 Bluetooth Digital Amplifier kit with IR cable, IR remote control , power adapter

VAI-3106D600  Wall Plate type Bluetooth Digital Amplifier Kit  with IR cable, IR remote control, power adapter

HR01-4K6G 4K HDMI 2.0 Repeater

• HDMI 2.0, HDCP 2.2/1.4 compliant.
• Support 1080p@60Hz 16bit,3D,HDR,4K@60Hz 4:4:4 18Gbps（6Gbps per color）.
• Support 4K@60Hz input 10M/output 10M, 4K@30Hz input 20M/Output 20M.
• CEC Pass through.
• Audio support LPCM 7.1 @ 192KHz、Dolby TrueHD、DTS-HD MA.
• Allow to connect multiple units for longer distance.
• Small and easy to install in any location.

DP02E 4K DisplayPort CAT5e Extender

• Extends DisplayPort signal over one CAT5e/6 cable.
• DP 1.2a. HDCP compliant.
• Uncompressed high definition video up to 4K UHD.
• Support 1080p@60Hz@16bits at 70M, 4K UHD
• Audio supports up to LPCM 7.1 @ 192KHz, Dolby TrueHD, DTS-HD MA

2018/2/6-9
Booth #5V50

GL001HP HDTVI/CVI/AHD/CVBS Power Isolator

• Prevents ground loop interference.
• Prevents the interference caused by power cables laid together with video/data cables.
• Support HDTVI/CVI/AHD/CVBS Video signal.
• Support UTC control (Up the coax).
• Input: DC12V
• Output: 600mA Max
• Eliminates picture tearing, crosstalk, rolling.

CA101HDP HDTVI/CVI/AHD/CVBS Video & Power over One Coax

• To send HD video and camera power over one coaxial cable.
• Transmission distance up to 400M (Max)
• Support power input: DC 24V – DC40V.
• Support camera power output: DC12V
• Package included one DC24V power adapter.

HAE01 4K HDMI Audio Extractor With Up/Down Scaler  1 in 2 out

• Support HDMI 2.0, HDCP 2.2, 4K@60Hz 4:4:4 18Gbps（6Gbps per color）3D,HDR.
• Support extracts the 4K HDMI audio and output to a multi-channel digital or analog audio signal.
• Allows you to route HDMI audio simultaneously via S/PDIF and 3.5mm stereo audio outputs.
• HDMI audio output: 1@192KHz, Dolby TrueHD, DTS-HD MA.
• Input: HDMI x 1, Output: HDMI x 2, Optical out x 1, analog stereo out x 1.
• Support uncompressed audio such as LPCM.
• Support 1080p to 4K upscale and 4K to 1080p downscale.
• Support HDCP 2.2 convert to HDCP 1.4.
• Support 4K 4:4:4 convert to 4:2:0.
• Audio output support: up to 7.1 channel
• Support CEC pass-through
• Built in EDID management, 2/5.1/7.1 patched EDID.
• Built in 5 way joystick switch for full OSD operation.

HE02EIX  4K 60Hz 4:4:4 HDMI with IR/RS232 CAT5e Extender 70M  

HE02EX   4K 60Hz 4:4:4 HDMI with IR/RS232 CAT5e Extender 100M

• Extends HDMI 4K UHD, RS232 and IR signal over one CAT5e/6 cable.
• HDMI 2.0, HDCP 2.2/1.4 & DVI Compliant.
• Support 4K UHD capability@60Hz with 4:4:4, HDR.
• Support 1080p@60Hz@48bits at 70M, 4K@60hz at 40M.(Model no: HE02EIX)
• Support 1080p@60Hz@48bits at 100M, 4K@60hz at 70M.(Model no: HE02EX)
• Transmitter built in local loop out for local display.
• Receiver built in dual HDMI output for two output display.
• Audio supports up to LPCM 7.1 @ 192KHz, Dolby TrueHD, DTS-HD MA
• Bi-directional IR, support 30-60khz.
• Bi-Directional RS232.
• Support CEC, EDID pass through
• 18Gbps (6Gbps per color)

IP04X90  Ultra High Power 90W POE Repeater 

• Extend of both power and data beyond 100 meters.
• Allow to use multiple repeaters for longer range.
• No external power required.
• Compatible with IEEE802.3af, IEEE802.3at,PoE+, LTPoE++
• Auto-sensing for detecting PoE or non-PoE devices.
• Support 10/100/1000Mbps transmission rate.
• Built in LED status indication.
• Perfect for long range outdoor POE camera use.
• Plug and play for easy installation.
• Allow to connect external power adapter when IP04X90 power is insufficient for multiple POE repeaters or long cable length application.

AD001HD1  HD-TVI/AHD/HDCVI to CVBS Converter Built in Loop Out

• Converts AHD/HD-TVI/CVI signal to composite video.
• Built in local loop output.
• Input support: AHD/HD-TVI/CVI, 720p@25/30, 720p@50/60hz, 1080p@25/30Hz.
• Output support: CVBS (Composite video), AHD/HD-TVI/CVI loop out
• Compact size.

HE01ERK Passive HDMI CAT5e Extender 

• Special design to extend HD DVR/NVR HDMI signal only.
• Include HE01SET transmitter, HE01SER receiver, used in pairs via one CAT5e/6 cable to send HDMI signal.
• HE01SER as active receiver for high performance.
• No external power required.
• Built in micro USB for external power when your HDMI source not able to provide enough power to the receiver.
• Support high resolution 1080p at 40M.
• Support long distance up to 70 meters at 1280x720.

HM44 4 x 4 HDMI  Multiviewer & Seamless Matrix Switcher 

• 4x4 seamless matrix for HDMI accepts four HD sources, scales and sizes each picture, and routes them to any or all of four HDTV displays without any switching delay or frame loss.
• 4 HDMI inputs and 4 scaled HDMI output.
• Support Matrix switcher, multivewer, video wall .
• Support 4 channel and 4 screens for seamless switching
• Support 4 channel video down/scaler.
• Support PIP/ POP/Quad multiview display.
• Control Options: Front panel buttons, IR remote control with OSD ( on-screen display), RS232, Ethernet with built in web browser.
• Support Android/iOS APP control.

HM41E 4 x 1 HDMI Quad/Multiviewer & Seamless Switcher (Support Auto-Switching) 

• Multiplexes 4 HDMI input into 1 HDMI output.
• Support resolution up to 1080p 60Hz.
• Support Scaler up to 1080p functions and digital audio format LPCM 2.0.
• Control option: IR remote control, front panel button.
• Support Quad multi-view and seamless switch.
• Support auto switching between 4 sources.
• Support different mode display: Quad, picture on picture (POP) and full screen display.
• Perfect for control remote machines and security monitoring systems, digital signage application.

AD001HD4 HDTVI/AHD/HDCVI/CVBS to HDMI/VGA/Composite Video Converter 

• Converts HD-TVI/AHD/CVI/NTSC/PAL/960H signal to HDMI, VGA, Composite Video or loop out.
• Input support: HD-TVI/AHD/HDCVI support: 720p@25/30/50/60, 1080p@25/30Hz.
• Output support: HDMI, VGA, Composite Video or loop out.
• 3 outputs could be display simultaneously.
• BNC connector function selection: loop output, composite video output or as second camera input.
• Built in PIP (display two input picture) under dual camera input mode.
• HDMI/VGA output support: 480p,576p,720p,1080i,1080p
  Composite video output support NTSC, PAL.
• Composite output built in underscan adjustment. (allow the edges of the picture fit well)
• Built in OSD to display input/output setting.
• HDMI and DVI compliant. (support DVI monitor by a HDMI to DVI adaptor)

HE05C HDMI over Coax Extender 500M (RF DVB-T) 

• Extend HDMI signal over coax up to 500M.
• Send HDMI signal over DVB-T RF Modulator technology
• Support point to point and multiple source devices to multi-display connections via CATV RF splitter/DTV Mixer.
• Support HDMI matrix solution over existing coax cable.
• Video encoding: H.264, support up to 1080P@30fps. Audio encoding: MPEG2
• Transmission distance up to 500m over coax cable.
• Support resolution up to 1080p@60Hz.
• Support up to 99 channel for both of TX/RX with frequency range 142-950Mhz
• TX/RX built in LCD display with edit channel setting.
• HE05CT transmitter built in HDMI loop out, channel ID setting by front panel button.
• HE05CR receiver input source selection could be from front panel button or optional IR remote controller.
• HDMI 1.3, HDCP 1.4, DVI 1.0 compliant.
• Applications for family cable TV transmission, hotels, hospitals, schools, video conference room, supermarket, malls, shops where need meeting video distribution, digital signage, student training broadcasting, DVD Blue Ray players video distribution, security monitoring system..etc.