Now we can have a goldfish in our house and will not have to worry about feeding it or changing water every now and them. Electronic Goldfish is here. Now you just have to put fresh batteries into the top, push the base decoration into
the bowl, fill the bowl with water, and put the top back on. Tap the top
and the goldfish "swims" around just like real goldfish.
SECAM, stands for "Sequential Color with Memory". It is an analog color television system first used in France. It is, historically, the first European color television standard.
Just as with the other color standards adopted for broadcast usage over the world, SECAM is a standard which permits existing monochrome television receivers predating its introduction to continue to be operate as monochrome television. Because of this compatibility requirement, color standards added a second signal to the basic monochrome signal, which carries the color information. The color information is called chrominance or C for short, while the black and white information is called the luminance or Y for short. Monochrome television receivers only display the luminance, while color receivers process both signals. Additionally, for compatibility, it is required to use no more bandwidth than the monochrome signal alone; the color signal has to be somehow inserted into the monochrome signal, without disturbing it. This insertion is possible because the spectrum of the monochrome TV signal is not continuous, hence empty space exists which can be utilized. This lack of continuity results from the discrete nature of the signal, which is divided into frames and lines. Analog color systems differ by the way in which empty space is used. In all cases, the color signal is inserted at the end of the spectrum of the monochrome signal.
SECAM differs from the other color systems by the way the R-Y and B-Y signals are carried. First, SECAM uses frequency modulation to encode chrominance information on the sub carrier. Second, instead of transmitting the red and blue information together, it only sends one of them at a time, and uses the information about the other color from the preceding line. It uses a delay line, an analog memory device, for storing one line of color information. This justifies the "Sequential, With Memory" name. Because SECAM transmits only one color at a time, it is free of the color artifacts present in NTSC and PAL resulting from the combined transmission of both signals. This means that the vertical color resolution is halved relative to NTSC. It is however not halved compared to PAL. Although PAL does not eliminate half of vertical color information during encoding, it combines color information from adjacent lines at the decoding stage, in order to compensate for "color sub carrier phase errors" occurring during the transmission of the Amplitude-Modulated color sub carrier. This is normally done using a delay line like in SECAM (the result is called PAL DL or PAL Delay-Line, sometimes interpreted as DeLuxe), but can be accomplished "visually" in cheap TV sets (PAL standard). Because the FM modulation of SECAM's color sub carrier is insensitive to phase (or amplitude) errors, phase errors do not cause loss of color saturation in SECAM, although they do in PAL. In NTSC, such errors cause color shifts.
There are five varieties of SECAM:
·French SECAM (SECAM-L)
·SECAM-B/G
·SECAM D/K
·SECAM-H
·SECAM-K
Unlike PAL or NTSC, analog SECAM television cannot easily be edited in its native analog form. Because it uses frequency modulation, SECAM is not linear with respect to the input image (this is also what protects it against signal distortion), so electrically mixing two (synchronized) SECAM signals does not yield a valid SECAM signal, unlike with analog PAL or NTSC. For this reason, to mix two SECAM signals, they must be demodulated, the demodulated signals mixed, and are remodulated again. Hence, post-production is often done in PAL, or in component formats, with the result encoded or transcoded into SECAM at the point of transmission. Reducing the costs of running television stations is one reason for some countries' recent switchovers to PAL.
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.
PAL - System of video transmission used in Europe and many other countries internationally
Pan and Scan - A procedure where a 4:3 image is taken from a widescreen source by clipping the edges.
Pixels - A Picture Element - the smallest element you can see on a monitor or television display. The more pixels an image contains, the higher its resolution.
Premiere - Video editing software packed created by Adobe Systems.
Progressive - Non-interlace full-frame footage or display device, so-called because a progressive image is displayed in one fast sweep, unlike interlaced images which are displayed in two passes, each pass displaying every other line.
Psychoacoustics - The theory of how the brain interprets audio.
Pulldown - This is the process of making multiple fields from frames in order to change the framerate of a source. Film footage is converted from 24fps to 30fps by creating 3 Fields out of the 2 fields usually contained in a single frame (i.e. 3:2 pulldown). PAL footage uses 2:2 pulldown where 2 fields are kept as 2 fields.
Quicktime - Software developed by Apple for the compression/decompression of video. Contains various codecs including Sorenson and recently Apple's own mpeg4 implementation.
Rainbow Artifacts/Moire - The yellow, purple (and other) coloured artifacts sometimes found on sharp black edges in video footage.
Resolution - The width and height of an image or display in pixels.
RGB - Red Green Blue, a method of storing video data by its red, green and blue components which combined make any colour of light you can see.
Ripping - the process of extracting (usually video) data from a file/format that is dificult to access/alter by normal methods. In particular in reference to the decryption process involved in extracting video data from DVDs. Also used to describe the same extraction process for CD audio and video or audio from games.
Sample Rate - The amount of audio samples every second in an audio stream. CDs are sampled 44100 times a seond.
Saturation - Related to chroma, you can think of saturation as how a colour looks under certain lighting conditions. For instance, a room painted a solid colour will appear different at night than in daylight.
SBC - Smart Bitrate Control, a method of accessing the Fast-motion and Slow-motion aspects of the DivX3.11a codec in order to allow variable bitrate encodes. Pioneered by Nando in his program Nandub.
Scanlines - the horizontal lines that comprise one video frame.
SECAM - System of video transmission used in France, similar to PAL - also plays at 25fps but has a different chroma carriers.
Sorenson - A compression codec available in Quicktime.
Spatial - To do with the 2d space element (i.e. the contents of a single frame) of video. For example, a spatial smoother smooths out blemishes that occur within an area of pixels.
Stereo - Audio that contains two audio channels, a left and a right.
Temporal - To do with the time dimension of video, i.e. the changes of the contents of a video in time. For example, a temporal smoother smooths out blemishes that occur on an individual pixel within a range (period) of frames.
Timecode - The method of interpreting frames in time for use in video editing within given standards (such as NTSC, PAL, Film etc) see also Drop-Frame Timecode.
Video for Windows - The main backbone for video compression codec within windows.
Virtualdub - an open source Windows program for capturing and doing simple editing/compressing of avi files.
VirtualdubAVS - an adpatation of Virtualdub by Belgador to allow easy access to AVIsynth scripts.
Wave - Another term for a (usually) uncompressed audio stream as it can be graphically represented by a waveform.
YUV - A method of storing video information that gives priority (more bits of data) to the luminance of a sample.
Maximum power rating: A value which means almost nothing, but is used nonetheless by manufacturers to entice the unsuspecting into purchasing their product based solely on the big number. Technically, it is the maximum wattage that an audio component can deliver/handle as a brief burst during a musical peak. Most reputable manufacturers will provide both an RMS and Max power rating. Typically, the given value for the maximum power rating is twice to three times that of RMS.
Microfarads: a measurement of capacitance (XC*10^-6).
Midrange (mids): the frequency range above bass but below treble that carries most of the identifying tones of music or speech. It is usually from 200Hz to 4kHz.
Millihenries (mH): a measurement of inductance (XL*10^-3).
Mms: the moving mass of a driver assembly.
Mono: monophonic sound. A method for reproducing sound where the signals from all directions or sources are blended into a single channel.
MOFSET: Metal Oxide Semiconductor Field Effect Transistors. Used in most modern, quality car audio amplifiers in the power supply. MOSFET's run cooler than normal bipolar transistors, and have a faster switching speeds and higher slew rates.
Octave: a range of tones where the highest tone occurs at twice the frequency of the lowest tone.
Ohm: a unit of electrical resistance or impedance.
Ohm's Law: a basic law of electric circuits. It states that: the current [I] in amperes in a circuit is equal to the voltage [V] in volts divided by the resistance [R] in ohms; thus, I = V/R.
Oversampling: It’s used in DAC systems. Increases signal frequency, making it easier for conversion circuitry and ancillary systems to filter out unwanted signals.
Out of Phase: When your speakers are mounted in reverse polarity, i.e., one speaker is wired +/+ and -/- from the amp and the other is wired +/- and -/+. Bass response will be very thin due to cancellation.
Output: the sound level produced by a loudspeaker.
Imaging - it is the speaker’s ability to localize different instruments playing simultaneously.
Impedance - dependent on frequency, it is the AC equivalent of resistance in a DC circuit.
Inductance (L) - the capability of a coil to store energy in a magnetic field surrounding it. It produces impedance to an AC current (jwL) and acts as a short circuit to DC. Inductors are commonly used in audio as low pass crossovers.
Infinite Baffle - a flat surface that completely isolates the back wave of a driver from the front.
Infrasonic (Subsonic) Filter - a filter designed to remove extremely low frequency usually between 8-25Hz or lower, noise from the audio signal. Useful for Ported box designs.
Input - connection from signal source.
Isobarik Enclosure - enclosure where one woofer is buried in the enclosure and a second is mounted up against the first and wired in reverse polarity (there are other variations for Isobarik designs), but this one works best. This allows the effective Vas of both drivers working in this push-pull configuration to be half that of a single identical driver mounted normally. Very small enclosures may be constructed as a result, with increased power handling. Less efficient than other designs, but the push pull configuration greatly reduces second order harmonic distortion. The name Isobarik comes from a term that means "constant pressure".
Keystoning - The process by which a projector optically or digitally racks an image onto the screen in order to compensate for sub-optimal placement with relation to the projection screen. Vertical keystoning is often necessary and recommended for business projectors which are table-mounted, but is always avoided in home theater use due to the fact that even a minimum amount causes pixel blurring and loss of detail.
Lens Shift - The ability of a projector (typically LCD or LCoS, but now DLP as well) to move the entire optical system such that the image can be adjusted/centered, without keystoning, onto the screen from a less-than-ideal projector placement.
Letterbox - This typically refers to the presence of black bars on the top and bottom of a film when displayed on a 4:3 or 16:9 displays.
Low-Pass Filter - an electric circuit designed to pass only low frequencies and act as high impedance to frequencies out of the filters pass band.
