In this report on television I will discuss television signals, the components the make up a television, and how a television produces the picture and sound for the final output.

The sound carrier is at the upper end of the spectrum. Frequency modulation is used to impress the sound on the carrier. The maximum frequency deviation is twenty-five kilohertz, considerably less than the deviation permitted by confessional FM stereo. As a result, a TV sound signal occupies less bandwidth in the spectrum than a standard FM broadcast station. Stereo sound is available in TV, and the multiplexing method used to transmit two channels of sound information is virtually identical to that used in stereo transmission for FM broadcasting.

The picture information is transmitted on a separate carrier located 4.5 MHz lower in frequency than the sound carrier. The video signal derived from a camera is used to amplitude modulate the picture carrier. Different methods of modulation are used for both sound and picture information so tha

In a TV transmitter, the sweep and sync circuits that creates the scanning signals for the vidicons or CCDs as well as generate the sync pulses that are transmitted along with the video and color signals. The sync signals, luminance Y and the color signals are added to form the final video signal that is used to modulate the carrier. Low-level AM is used. The final AM signal is amplified by very high power linear amplifiers and sent to the antenna via a diplexer.

The sync pulses are also fed to an IC that takes the horizontal sync pulses during the vertical blanking interval and integrates them into a 60 Hz sync pulse that is used to synchronixe a vertical sweep oscillator. The output from this oscillator is a sawtooth sweep voltage at the field rate of 60 Hz. This output is amplified and converted into a linear sweep current that drives the magnetic coils in the picture tube yoke. These coils produce vertical deflection of the electron beams in the picture tube.

The 3.58 MHz subcarrier is supressed by the balanced modulators and therefore is not transmitted. Only the filtered upper and lower sidebands of the color signals are transmitted. To demodulate these double-sideband AM signals, the carrier must be reinserted at the receiver. A 3.58 MHz oscillator in the receiver generates the subcarrier for the balanced modulator-demodulator circuits.

The video signal is most often generated by a TV camera, a very sophisticated electronic device that incorporates lenses and light-sensitive tranducers to convert the scene or object to be viewed into an electrical signal that can be used to modulate a carrier. To do this, the scene to be transmitted is collected and focused by a lens upon a light-sensitive imaging device. Both vacume tube and semiconductor devices are used for converting the light information in the scene into an electrical signal. The scene is divided into smaller segments that can be transmitted serially over a period of time. It is the job of the camera to subdivide the scene in an orderly manner so that an acceptable signal is developed. This process is called scanning.

The output of the video detector is the Y signal or the composite color signal, which are amplified by the video amplifiers. The Y signal is used to create an AGC voltage output for controlling the gain of the IF amplifiers and mixers.

At the same time the voice or sound signals frequency modulate a carrier that is amplified by class C amplifiers and fed to the same antenna by way of the diplexer. The resulting VHF or UHF signal travels by line-of-sight propagation to the antenna and receiver.

Some common words found in the essay are:
VHF UHF, KHz Dividing, United TV, B&W TV, Fundamentals Television, Additional TV, picture tube, color signals, video signal, sync pulses, 358 mhz, electron beam, mhz subcarrier, 358 mhz subcarrier, red green blue, tv sets, green blue, tv signal, coils picture tube, horizontal sync pulses, color signals transmitted,
Approximate Word count = 6955
Approximate Pages = 28 (250 words per page double spaced)