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A jungle chip, or jungle IC, is an
integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...
(IC or "chip") found in many
analog television Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, instantaneous phase and frequency, ...
s from the 1970s and all of them by the early 1990s. It takes a
composite video Composite video, also known as CVBS (composite video baseband signal or color, video, blanking and sync), is an analog video format that combines image information—such as brightness (luminance), color (chrominance), and synchronization, int ...
signal from the
radio frequency Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of a magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around . This is roughly between the u ...
receiver electronics and turns it into separate
RGB The RGB color model is an additive color model in which the red, green, and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three ...
outputs that can be sent to the
cathode ray tube A cathode-ray tube (CRT) is a vacuum tube containing one or more electron guns, which emit electron beams that are manipulated to display images on a phosphorescent screen. The images may represent electrical waveforms on an oscilloscope, a ...
to produce a display. This task had previously required separate analog circuits. Early jungle chips appeared in the 1970s. These were entirely analog devices, which decoded the original signal into RBG and did little else. Later versions normally included a second set of inputs in RGB format that were used to overlay
on-screen display An on-screen display (OSD) is an image superimposed on a screen picture, commonly used by modern television sets, VCRs, and DVD players to display information such as volume, channel, and time. History In the past, most adjustments on TV set ...
imagery. These would be connected to a
microcontroller A microcontroller (MC, uC, or μC) or microcontroller unit (MCU) is a small computer on a single integrated circuit. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals. Pro ...
that would be included to handle operations like tuning, sleep mode and running the
remote control A remote control, also known colloquially as a remote or clicker, is an consumer electronics, electronic device used to operate another device from a distance, usually wirelessly. In consumer electronics, a remote control can be used to operat ...
. A separate input called "blanking" switched the jungle outputs between the two inputs on the fly. This was normally triggered at a fixed location on the screen, creating rectangular areas with the digital data overlaying the television signal. This was used for on-screen channel displays,
closed captioning Closed captioning (CC) is the process of displaying text on a television, video screen, or other visual display to provide additional or interpretive information, where the viewer is given the choice of whether the text is displayed. Closed cap ...
support, and similar duties. The internal RGB inputs have led to such televisions having a revival in the
retrocomputing Retrocomputing is the current use of Vintage computer, older computer hardware and software. Retrocomputing is usually classed as a hobby and recreation rather than a practical application of technology; enthusiasts often collect rare and valuabl ...
market. By running connectors from the RGB pins on the jungle chip to connectors added by the user, typically RCA jacks on the back of the television case, and then turning on the blanking switch permanently, the system is converted to an RGB monitor. Since early computers output signals with television timings,
NTSC NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170. In 1953, a second ...
or
PAL Phase Alternating Line (PAL) is a color encoding system for analog television. It was one of three major analogue colour television standards, the others being NTSC and SECAM. In most countries it was broadcast at 625 lines, 50 fields (25 ...
, using a jungle chip television avoids the need to provide separate timing signals. This contrasts with multisync monitors or similar designs that do not have any "built-in" timing and have separate inputs for these signals. Examples of jungle chips include the Motorola MC65585, Philips TDA6361 and Sony CXA1870.


References

* * * {{electronics-stub Integrated circuits Analog video connectors