"Radio and Television" How to Transmit Information—Introduction to Communication Technology PPT Courseware 2

Description

"Radio and Television" How to Transmit Information—Introduction to Communication Technology PPT Courseware 2

1. Audio, video and radio frequency signal modulation

1. The principle of electromagnetic waves transmitting sound and image signals

Electromagnetic waves carry sound and image signals just like pigeons carry messages.

First, the signal is carried on the electromagnetic wave, and then the electromagnetic wave carrying the signal is emitted, and when it reaches the receiving location, the signal is detected from the electromagnetic wave.

2. The emission process of electromagnetic waves

(1) A high-frequency oscillation current---radio frequency signal is generated by a high-frequency oscillator.

(2) Convert the sound---audio signal and image---video signal to be transmitted into a current signal (electrical signal)

(3) Input the high-frequency oscillation current generated by the oscillator and the signal current of sound and image into the modulator - modulation, so that the high-frequency oscillation current changes accordingly with the transmitted sound and image signal, and then the The high-frequency oscillating current is sent to the transmitting antenna, and the emitted electromagnetic wave carries the sound and image signal to be transmitted. That is, the so-called "adding" the signal to be transmitted to the electromagnetic wave. The electromagnetic wave with the signal is emitted.

2. Transmission and reception of radio broadcasts

1. The transmission process of radio broadcasting

2. Radio reception process

(1) Use an antenna to receive electromagnetic waves.

(2) Use a tuner, which is the channel selection circuit in a radio or television, to select the required electrical signal.

(3) By letting the high-frequency oscillating current pass through the detector, the sound signal and image signal to be transmitted can be "detected" from the high-frequency oscillating current. By sending the sound signal and image signal to the speaker and the TV respectively, Hear sounds and see images.

During extracurricular activities, several students discussed the reception and transmission of radio broadcasts and television signals. They made the following statements. Which one do you think is correct? ( )

A. Radio broadcasting is the mutual conversion between optical and electrical signals.

B. The reception or emission of television signals is the conversion between acoustic and electrical signals.

C. Both radio broadcasting and television are the conversion of light and electrical signals.

D. Whether it is radio broadcasting or television, there is conversion of sound and electrical signals.

Analog and digital signals

Analog signal: The frequency and amplitude of the current all "imitate" changes in the frequency and amplitude of the sound.

Digital signal: Text, sound, and images are all encoded with binary numbers "0" and "1".

Keywords: How to deliver the introduction to information and communication technology teaching courseware, radio and television teaching courseware, Beijing Normal University edition ninth-grade physics PPT courseware download, second volume, ninth-grade physics slide courseware download, how to deliver the introduction to information and communication technology PPT courseware download, broadcast and TV PPT courseware download, in .PPT format;

For more information about the PPT courseware "How to deliver an introduction to information and communication technology on radio and television", please click on the "How to deliver an introduction to information and communication technology ppt radio and television ppt" tag.

How "Radio and Television" transmits information - Introduction to communication technology PPT courseware 6:

"Radio and Television" Introduction to Information and Communication Technology PPT Courseware 6 1. The principle of electromagnetic waves transmitting sound and image signals Electromagnetic waves transmit sound and image signals just like pigeons sending letters. The signal is first carried on the electromagnetic wave, and then the signal is carried on the electromagnetic wave. Electromagnetic wave emission..

How "Radio and Television" transmits information - Introduction to communication technology PPT courseware 5:

"Radio and Television" How to Deliver Information and Communication Technology Introduction PPT Courseware 5 Think about it: Electromagnetic waves are generated by changing currents. When you turn on a fluorescent lamp, you will hear noise from a nearby radio. This noise is caused by the interruption of circuits. Continuous current flows around...

How "Radio and Television" transmits information - Introduction to communication technology PPT courseware 4:

"Radio and Television" How to Deliver Introduction to Information and Communication Technology PPT Courseware 4 Review: 1. How are electromagnetic waves generated? How to indirectly observe its existence through experiments? Electromagnetic waves are produced by changing electric currents and are heard on a nearby radio when a fluorescent lamp is turned on..

File Info

Update Time: 2024-11-21

This template belongs to Physics courseware Beijing Normal University Ninth Grade Physics Volume 2 industry PPT template

Preview