Flipside of Technology

This lady has now changed her habit of how she lists her names on her mobile phone after her handbag was stolen. Her handbag, which contained her cell phone, credit card, wallet... etc... was stolen.
20 minutes later when she called her hubby, from a pay phone telling him what had happened, hubby says 'I received your text asking about our Pin number and I've replied a little while ago.'
When they rushed down to the bank, the bank staff told them all the money was already withdrawn. The thief had actually used the stolen cell phone to text 'hubby' in the contact list and got hold of the pin number. Within 20 minutes he had withdrawn all the money from their bank account.

Moral of the lesson:
Do not disclose the relationship between you and the people in your contact list.
Avoid using names like Home, Honey, Hubby, Sweetheart, Dad, Mom, etc....
And very importantly, when sensitive info is being asked through texts, CONFIRM by calling back.
Also, when you're being text by friends or family to meet them somewhere, be sure to call back to confirm that the message came from them. If you don't reach them, be very careful about going places to meet 'family and friends' who text you.

www.switch2life.com 

Telemedicine

Telemedicine is a rapidly developing application of clinical medicine where medical information is transferred through the phone or the Internet and sometimes other networks for the purpose of consulting, and sometimes remote medical procedures or examinations. Telemedicine can be simplly defined as two health professionals discussing a case over the telephone, or as complex as using satellite technology and video-conferencing equipment to conduct a real-time consultation between medical specialists in two different countries. Telemedicine generally refers to the use of communications and information technologies for the delivery of clinical care.

Care at a distance is an old practice which was often conducted via post. There has been a long and successful history of in absentia health care which, thanks to modern communication technology, has evolved into what we know as modern telemedicine. In its early manifestations, African villagers used smoke signals to warn people to stay away from the village in case of serious disease. In the early 1900s, people living in remote areas in Australia used two-way radios, powered by a dynamo driven by a set of bicycle pedals, to communicate with the Royal Flying Doctor Service of Australia.

The terms e-health and telehealth are at times wrongly interchanged with telemedicine. Like the terms "medicine" and "health care", telemedicine often refers only to the provision of clinical services while the term telehealth can refer to clinical and non-clinical services such as medical education, administration, and research.

www.switch2life.com

NTSC VIDEO

NTSC is short for National Television System Committee. The NTSC is responsible for setting television and video standards in the United States. The NTSC standard for television defines a composite video signal with a refresh rate of 60 half-frames i.e. interlaced per second. Each frame contains 525 lines and can contain 16 million different colors. The NTSC standard is incompatible with most computer video standards, which generally use RGB video signals. However, you can insert special video adapters into your computer that convert NTSC signals into computer video signals and vice versa.

NTSC color encoding is used with the system M television signal, which consists of 29.97 interlaced frames of video per second, or the nearly identical system J in Japan. Each frame consists of a total of 525 scan lines, of which 486 make up the visible raster. The remainder are used for synchronization and vertical retrace. This blanking interval was originally designed to simply blank the receiver's CRT to allow for the simple analog circuits and slow vertical retrace of early TV receivers. However, some of these lines now can contain other data such as closed captioning and vertical interval time code (VITC). In the complete raster, the even-numbered or 'lower" scan lines (Every other line that would be even if counted in the video signal, e.g. {2,4,6,...,524}) are drawn in the first field, and the odd-numbered or "upper" (Every other line that would be odd if counted in the video signal, e.g. {1,3,5,...,525}) are drawn in the second field, to yield a flicker-free image at the field refresh frequency of approximately 59.94 Hertz (actually 60 Hz/1.001). For comparison, 576i systems such as PAL-B/G and SECAM uses 625 lines (576 visible), and so have a higher vertical resolution, but a lower temporal resolution of 25 frames or 50 fields per second.

The actual figure of 525 lines was chosen as a consequence of the limitations of the vacuum-tube-based technologies of the day. In early TV systems, a master voltage-controlled oscillator was run at twice the horizontal line frequency, and this frequency was divided down by the number of lines used (in this case 525) to give the field frequency (60 Hz in this case). This frequency was then compared with the 60 Hz power-line frequency and any discrepancy corrected by adjusting the frequency of the master oscillator. For interlaced scanning, an odd number of lines per frame were required in order to make the vertical retrace distance identical for the odd and even fields, which meant the master oscillator frequency had to be divided down by an odd number. At the time, the only practical method of frequency division was the use of a chain of vacuum tube multi-vibrators, the overall division ratio being the mathematical product of the division ratios of the chain. Since all the factors of an odd number also have to be odd numbers, it follows that all the dividers in the chain also had to divide by odd numbers, and these had to be relatively small due the problems of thermal drift with vacuum tube devices. The closest practical sequence to 500 that meets these criteria was 3 × 5 × 5 × 7 = 525.

www.switch2life.com

Interlaced Video

Interlaced video is a technique of doubling the perceived frame rate of a video signal without consuming extra bandwidth. Since the interlaced signal contains the two fields of a video frame shot at two different times, it enhances motion perception to the viewer and reduces flicker by taking advantage of the persistence of vision effect. This results in an effective doubling of time resolution as compared with non-interlaced footage. However, interlaced signals requires a display that is natively capable of showing the individual fields in a sequential order, and only traditional CRT-based TV sets are capable of displaying interlaced signals, due to the electronic scanning and lack of apparent fixed-resolution. Interlaced scan refers to one of two common methods for "painting" a video image on an electronic display screen by scanning or displaying each line or row of pixels. This technique uses two fields to create a frame. One field contains all the odd lines in the image, the other contains all the even lines of the image. A PAL-based television display, for example, scans 50 fields every second i.e. 25 odd and 25 even. The two sets of 25 fields work together to create a full frame every 1/25th of a second, resulting in a display of 25 frames per second, but with a new half frame every 1/50th of a second.

To display interlaced video on progressive scan displays, de-interlacing is applied to the video signal.

One of the most important factors in analog television is signal bandwidth which is measured in megahertz. The greater the bandwidth, the more expensive and complex is the entire production and broadcasting chain which consist of cameras, storage systems such as tape recorders or hard disks, broadcast and reception systems such as terrestrial, cable, and satellite transmitters and receivers, or the Internet, and end-user displays such as televisions or computer monitors. Given a fixed bandwidth instead, interlace can provide a video signal with twice the display refresh rate for a given line count versus progressive scan video at similar frame rate, for instance 1080i at 60 half-frames per second, vs. 1080p at 30 full frames per second. The higher refresh rate improves the portrayal of motion, because objects in motion are captured and their position is updated on the display more often, and when objects are more stationary the human vision combines information from multiple similar half-frames resulting in the same perceived resolution as progressive full frames. This technique is only useful though, if the source material is available in higher refresh rates. Cinema movies are typically recorded at 24fps, and gets no real benefit from common interlacing techniques.

www.switch2life.com

Electronic's Terms .......... Part 4

DAC – Digital to Analogue converter, turning on/off pulses into analogue sound. CD players have DACs built in. Separate DACs can upgrade a CD player or other digital player/ recorder, or can be used with dedicated CD transports.

Damping - the reduction of movement of a speaker cone, due either to the electromechanical characteristics of the speaker driver and suspension, the effects of frictional losses inside a speaker enclosure, and/or by electrical means.

Damping Factor - This is a quantity which defines how quickly the amplifier can stop a reproduced frequency such as a bass note. The higher the damping factor, the better the amp will control the woofer and help reduce overhang distortion. The damping factor of an amplifier is mostly dependent on the quality of the power supply which feeds the power amp.

Damping Material - any material added to the interior of a speaker enclosure to absorb sound and reduce out-of-phase reflection to the driver diaphragm (cone). Usually acoustic fiberglass, polyester batting, or Polyfill is used in speaker enclosures.

Decibel (dB) - (1) a logarithmic scale used to denote a change in the relative strength of an electric signal or acoustic wave. It is a standard unit for expressing the ratio between power and power level. Using the logarithmic relationship for power PdB = 10*log[Pout/Pin] , a doubling of electrical power only yields an increase of +3 dB. Increasing the power tenfold will yield an increase of +10 dB and is a doubling of perceived loudness. The decibel is not an absolute measurement, but indicates the relationship or ratio between two signal levels. (2) SPL (sound pressure level) can be measured in dB. 0 dB represents the threshold of normal human hearing, 130 dB represents the threshold for pain, 140 dB causes irreparable hearing damage, and 150 dB can cause instant deafness, anything greater than about 192 dB can kill you.

De-interlaced video - Most video sources, including DVD, standard-definition TV, and 1080i high-definition TV, transmit interlaced images. Instead of transmitting each video frame in its entirety (what is called progressive scan), most video sources transmit only half of the image in each frame at any given time. Deinterlacing is the process of stitching back together, properly, the individual fields into a solid frame of video.

Diaphragm - the part of a dynamic loudspeaker attached to the voice coil that moves and produces the sound. It usually has the shape of a cone or dome.

Diffusion - The scattering of sound.

Dipole - A speaker design which generates equal amounts of sound both forward and backward, with the two sounds being out of phase. Dipoles are often used as surround speakers.

Direct Current (DC) - current in only one direction.

Diffraction - a change in the direction of a wave that is caused by the wave moving past or hitting an obstacle.

Dispersion - the spreading of sound waves as it leaves a speaker.

Distortion - any undesirable change or error in the reproduction of sound that alters the original signal.

Dome Tweeter - a high frequency speaker driver with a dome-shaped diaphragm usually made of metal or silk.

Driver - a loudspeaker unit, consisting of the electromagnetic components of a speaker, typically a magnet and voice coil.

DRM - a term referring to technologies used to control usage of digital media - including hardware controls to deactivate unauthorized use.

Dynamic range - the range of sound intensity a system can reproduce without compressing or distorting the signal.

www.TheAmitabh.com

Electronics Terms .......... Part 2

Baffle - a board or other planar surface used to mount a loudspeaker.

Bandwidth - the range of frequencies reproduced by an Amplifier or transducer.

Band-Pass Enclosure - type of enclosure used for subwoofers where the driver is completely inside the enclosure and all of the output emerges through a port(s). This configuration is usually designed for high output volume with importance of accuracy/fidelity being less emphasized.

Band-Pass filter - an electric circuit designed to pass only midrange frequencies. This filter acts as high impedance to frequencies out of the pass band.

Bass (low frequencies) - The low end of the audio frequency spectrum between 0Hz to about 200 Hz.

Bi-amping and bi-wiring - some higher performance speakers  include dual sets of connectors, usually the type known as "binding posts," Models with dual connectors almost always also feature a special type of crossover with separate "high-pass" and "low-pass" sections. These connectors may also be shunted together with jumpers to accommodate conventional hook-ups.

Bi-wiring - low and high frequency sections of the loudspeaker are separated electrically at the cross-over. Each driver unit has its own filter section and connection terminals. Both sets of terminals are connected to one amplifier.

Bi-amping - an extension of bi-wiring in that a separate amplifier is utilized for each of the two sets of connectors from the cross-over.

Bipole - A speaker design which generates equal amounts of sound both forward and backward, with the two sounds being "in phase".

www.TheAmitabh.com

Electronics Terms .......... Part 1

Acoustic suspension – It is a sealed or closed box speaker enclosure, also referred to as an infinite baffle. Acoustic suspension speaker systems are generally less efficient than Bass Reflex or Transmission Line designs, but may offer greater accuracy with respect to bass tightness and reproduction.

Acoustics - the science or study of sound.

Alternating (AC) Current - currents that have harmonic time dependence.

Ampere (A) – Ampere is the unit of measurement for electrical current in coulombs per second.

Amplifier - an electrical circuit designed to increase the current or voltage of an applied signal.

Amplitude - the relative magnitude of a signal.

Anamorphic - This term is used, and often misused, in a variety of ways. To the laymen it is most easily described in terms of a DVD or image that has been condensed horizontally in order that the source component or output device can make use of more, or all, of the available pixel data on the source media (typically a DVD or HD-DVD). Anamorphic or CinemaScope lenses can work in conjunction with a dedicated video processor to render a constant height image properly onto a 2.4:1 screen.

Aspect Ratio - This refers to a ratio between the width and height of a display or image. Typical aspect ratios include 4:3 (also called 1.33:1), 16:9 (also called 1.78:1), 1.85:1 and 2.4:1.

Attenuation - the reduction of an electrical signal.

Audio frequency - the acoustic spectrum of human hearing, generally regarded to be between 20 Hz and 20 kHz.

www.switch2life.com