Who invented the Audio Amplifier?

The audio amplifier was invented in 1909 by Lee de Forest when he invented the triode vacuum tube. The triode was three terminal device with a control grid that can modulate the flow of electrons from the filament to the plate. The triode vacuum amplifier was used to make the first AM radio.

Early audio amplifier were based on vacuum tubes which is also known as valves, and some of these achieved notably high quality like the Williamson Amplifier. Most modern audio amplifiers are based on solid state devices (transistors such as BJT, FET, and MOSFET), but there are still some who prefer tube-based amplifier, due to perceive 'warmer' valve sound. Audio amplifier based on transistors became practical with the wide availability of inexpensive transistors in the late 1960s.

• Williamson amplifier

LCD vs DLP Projectors

LCD Projectors

Advantages

• Richer color dynamics for better results
  in rooms with ample ambient light.
•  Draw less power
•  Throw less heat
•   No color wheel = No "Rainbow Effect"
•  Slightly quieter, seemingly
  sharper image on data.

Disadvantages

•  More visible pixels
• Some screen doors effect on certain video
•   Physically larger- Even for some number of lumens
•  Poor contrast
•  Blacks comes out lighter 

 DLP Projectors

Advantages

• Smooth video
• Smaller box
• Pixels far less visible
   (Although normally not an issue for business use.)
•  More "filmlike" on DVD and HDTV
• Generate "BLACKER" blacks
• Higher contrast

  Disadvantages

•  Rainbow effects bothers some
•  More moving parts ( color filter wheel)
•  Poorer reds and yellows at full power.
• Need more lumens than LCD for rich colors when dealing with ambient light.

Choosing The Right Specs For Your CCTV

I’ve been in UAE for almost two years now. I’ve been for many type of installation. AV, CCTV, Data.. etc.
I’ve been assigned to install a CCTV system to one of our client. It was just a simple CCTV installation, 2 dome cameras, 4 ch DVR and a monitor. When I finished the installation, I then configure the system and noticed the resolution of the camera is not quite good. I’m wondering the problem is with the cable we used, so what I did is I removed the camera then connected it directly to the DVR with a short cable. Still it has a poor image.
Luckily the client didn’t notice the poor image, maybe because he was too happy to have a CCTV system in his office.
When I arrived at home, I tried to open the internet about CCTV cameras and this is what I’ve seen.
Types of CCTV camera:
1. Indoor Cameras.
– As the name implies, indoor camera is used for indoor security purposes. Used mostly in homes, school, offices, hotels and depending upon the security needs.

2. Outdoor Cameras.
– Camera used for outdoor purposes. Mostly used in the entrances and exits of the buildings. It is usually place in an enclosure or a hard shell vandal proof casing.

3. IR Day/ Night Camera
– Mostly used in high alert security areas for 24 hour surveillance.  In day time, this camera functions as a normal camera while in night time it automatically switches low-lux black and white mode and infrared automatically illuminated for full surveillance at night.

4. Dome Camera
– Dome camera is usually installed in public areas such train stations, terminal stations, etc… It is usually installed inside a dark  dome so that it would not be noticeable.  This camera can be rotated or tilted manually.

5. Vandal Proof Camera.
– Usually used as an outdoor camera. This camera is sheltered by  solid enclosure and is covered by a break- proof glass which does not effect its video streaming. This camera is recommended for high surveillance area.

With this types of camera, we can now assume what camera we needed for depending our specifications.
This are the specifications for the camera you have to choose for so that you would have a perfect surveillance system.
1. Focal length
The Focal Length is measured in mm. As a guide:
a short focal length (e.g. 2.5mm) = a wide angle of view
a long focal length (e.g. 16mm) = a narrow angle of view
the smaller the CCD Chip – the narrower the angle of view
2. Depth of Field
The Depth of View is the distance within which objects in a picture are in focus.
A large Depth of Field means almost all objects in the Field of View are in focus.
A small Depth of Field means only a small section of the Field of View are in Focus.
The following factors can lead to a greater Depth of Field:

• Using a Wide Angle Lens
• High F-Stop
• Using an Auto Iris
• Camera Format

The size of the camera’s CCD image device will affect the angle of view. CCTV Cameras come in different chip sizes – 2/3″, 1/2″, 1/3″ and 1/4″.

Approximate Horizontal angles of view for CCD Chip Cameras
Focal Length	2/3″	1/2″	1/3″	1/4″
2.0mm	-	-	-	82
2.8mm	-	-	86	57
4.0mm	-	77	67	47
4.8mm	83	67	57	40
6.0mm	70	56	48	32
8.0mm	56	44	36	25
12mm	39	30	25	17
16mm	30	23	17	13
25mm	18	15	12	8
50mm	10	7	6	4

3. F Stop

F Stop or Aperture has 2 measurements. When the lens is fully open (Maximum Aperture / Minimum F-Stop), just before the lens completely closes (Minimum Aperture / Maximum F-Stop).
F Stop – is the lenses ability to gather light depending on the aperture and focal length.

4. C or CS Mount

The 2 standard cctv camera lens mounts. The difference between the two is simply the distance between the lens and the ccd image sensor. C Mount – 17.5mm CS Mount – 12.5mm

5. Auto or Manual Iris

For changing light conditions (e.g. cameras positioned outdoors), Auto Iris lenses are needed.
For indoor use manual iris lenses are sufficient as light levels will not vary too much.

6. Video or Direct Drive

The majority of CCTV Cameras will be able to use both types. Video Drive Lenses contain circuitry which converts video signal from the camera into iris control. Direct Drive Lenses require the cctv camera to contain the circuitry.

What is VGA?

VGA or Video Graphic Array

          Refers specifically to the display hardware first introduced with the IBM PS/2 line of computers in 1987,but through its widespread adoption has also come to mean either an analog computer display standard, the 15-pin D-subminiature VGA connector or the 640×480 resolution itself. While this resolution has been superseded in the personal computer market, it is becoming a popular resolution on mobile devices.

          Video Graphics Array (VGA) was the last graphical standard introduced by IBM that the majority of PC clonelowest common denominator that all PC graphics hardware supports, before a device-specific driver is loaded into the computer. For example, the MS-Windows splash screen appears while the machine is still operating in VGA mode, which is the reason that this screen always appears in reduced resolution and color depth. manufacturers conformed to, making it today (as of 2009) the
VGA was officially superseded by IBM's XGA standard, but in reality it was superseded by numerous slightly different extensions to VGA made by clone manufacturers that came to be known collectively as "Super VGA".


Pin Configuration

Pin out
A female DE15 socket (videocard side).
Pin 1	RED	Red video
Pin 2	GREEN	Green video
Pin 3	BLUE	Blue video
Pin 4	ID2/RES	formerly Monitor ID bit 2, reserved since E-DDC
Pin 5	GND	Ground (HSync)
Pin 6	RED_RTN	Red return
Pin 7	GREEN_RTN	Green return
Pin 8	BLUE_RTN	Blue return
Pin 9	KEY/PWR	formerly key, now +5V DC
Pin10	GND	Ground (VSync, DDC)
Pin 11	ID0/RES	formerly Monitor ID bit 0, reserved since E-DDC
Pin 12	ID1/SDA	formerly Monitor ID bit 1, I²C data since DDC2
Pin 13	HSync	Horizontal sync
Pin 14	VSync	Vertical sync
Pin 15	ID3/SCL	formerly Monitor ID bit 3, I²C clock since DDC2
The image and table detail the 15-pin VESA DDC2/E-DDC connector; the diagram’s pin numbering is that of a female connector functioning as the graphics adapter input. In the male connector, this pin numbering corresponds with the mirror image of the cable’s wire-and-solder side.

 

Video Conferencing

Any idea about video conferencing? 

Q. What is video conferencing?


A. A videoconference or video conference (also known as a videoteleconference) is a set of interactive telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously. It has also been called 'visual collaboration' and is a type of groupware.
Videoconferencing differs from a videophone calls in that its designed to serve a conference rather than individuals. It is an intermediate form of videotelephony, first deployed commercially by AT&T during the early 1970s using their Picturephone technology. (wikipedia)

Q. Do we really need video conferencing?

A. Not really, but videoconferencing can provide us a better way of communication between you and another else in somewhere places.

Q. What should I need if I want to have a videoconferenecing for my personal use?

A. If you want a videoconferencing, you must need a PC with internet connection and same with the person you want to communicate with. You must have a program install in both PC that can be used for video conferencing such as Yahoo messenger or Skype. The PC must have a camera, speaker and a microphone so that you two both can see and hear each other.

Q. For a business sector, what equipment / device is mostly use for video conferencing?
 
A. They are several equipments use for video conferencing. You can use Sony, they have different equipment and models for video conferencing same as Polycom and Tandberg.


For more question about video conferencing. click here

TRUMP Nakheel Sales Office

Combine image of two Christie DS+60 single chip projector.

   

Five Christie DW 5k  3 chip DLP projector with TWIST module for the curve wall image. Image size is approximately 6'x45'.

For the floor image, four Christie DW 5k  with an image size of 12'x18'. Nineteen Rosco X24 X-Effects projectors for the water effects.








more pics...

AV Racks

Project

I would be posting soon some of our finished and recent AV projects.

About Joseph Lamban

Joseph Lamban took up Bachelor of Science of Electronics and Communications Engineering in one of the universities in the Philippines. As he graduated college, he work as a Service Engineer in one of the company located in Makati. But he really feel bored in his work then decided to leave in the company. Then found a work in one of the company in FCIE (First Cavite Industrial Estate) as a Maintenance Engineer. The work is not really related on what he studied during college years but started to love his work. It's a very tough job. You really have to use your physical strength and mind. Six months after he decided to leave the company and wanted to get a job which is really related to his course.

He found his next job. He worked in one of the industrial area in Cavite, as a Equipment Engineer. But still i decided to leave the company.

His brother was working in Dubai. His brother asked him if he want to go to Dubai and he say yes. So then his brother got him a visit visa going to Dubai.

He got his first job as a AV Installation Engineer in Dubai.

It is a tough professions. At first it was really a tough job for him because he don't have any experienced related with AV. He is been working as an AV Installation Engineer for almost 2 years.

He made this blog so that he can share his knowledge and idea as AV Installation Engineer.