1 / 18

RADIO AND TELEVISION BROADCASTING

RADIO AND TELEVISION BROADCASTING. AM Radio FM Radio Television. 3.4.1 AM Radio Broadcasting . AM Radio Broadcasting 535-1605 kHz 10 kHz carrier spacing bandwidth of m(t) is 5kHz. Superheterodyne receiver with intermediate frequency

donny
Download Presentation

RADIO AND TELEVISION BROADCASTING

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. RADIO AND TELEVISION BROADCASTING • AM Radio • FM Radio • Television

  2. 3.4.1 AM Radio Broadcasting • AM Radio Broadcasting • 535-1605 kHz • 10 kHz carrier spacing • bandwidth of m(t) is 5kHz. • Superheterodyne receiver with intermediate frequency • two frequency components and are produced after the mixer

  3. Rejection of the radio signal at the image frequency • Assume there are two received signals • The mixer output consists of the two signals • The RF amplifier bandwidth is designed to be sufficiently narrow so that the image frequency signal is rejected • The IF amplifier has bandwidth of 10kHz to reject signal from adjacent channels. Desired signal Interference from image channel

  4. 3.4.2 FM Radio Broadcasting • FM Radio Broadcasting • for transmission of voice and music signals (bandwidth of m(t) is 15 kHz) • 88 - 108 MHz • 200 kHz carrier spacing • peak-frequency deviation 75 kHz • Superheterodyne receiver with intermediate frequency

  5. FM-Stereo Broadcasting • Many FM-stereo stations transmit music programs in stereo by using the outputs of two microphones. • A pilot tone at the frequency of 19 kHz is added to the signal for the purpose of demodulating the DSB-SC AM signal. • A monophonic FM receiver can recover the summed signal L+R by using a conventional FM demodulator. Hence, the FM-stereo broadcasting is compatible with the conventional FM.

  6. FM Stereo Transmitter

  7. FM Stereo Receiver

  8. 3.4.3 Television Broadcasting • Commercial TV broadcasting began as black-and-white picture transmission by BBC in 1936. • The two dimensional image is converted to a one-dimensional electrical signal by sequentially scanning the image. • The scanning of the electron beam in the CRT is controlled by two voltage applied across the horizontal and vertical deflection plates. • In commercial TV broadcasting, the bandwidth of the video signal is is limited to W = 4.2 Mhz. • VSB modulation is employed, the total transmission bandwidth is around 6 Mhz.

  9. Interlaced pattern with rate 1/60 sec

  10. A typical video signal

  11. The audio portion of the TV signal is transmitted is limited to W= 10 kHz. • The peak frequency deviation in the FM-modulated signal is selected as 25 kHz, and the FM-signal needs bandwidth of 70 kHz.

  12. 3.5 Mobile Radio Systems • Cellular concept

  13. Terminologies • The simultaneous transmission between two parties is called full-duplex operation. • In analog cellular system, the 3 kHz audio signal is transmitted via FM using a channel bandwidth of 30 kHz. This represents a bandwidth expansion of approximately a factor of 10.

More Related