ĐIỆN tử VIỄN THÔNG DTVT2 nhom1 bai6 khotailieu

NHÓM – LỚP Đ8-ĐTVT - LƯƠNG NGỌC LONG HỒNG NGỌC TRUNG HỒNG THỊ LINH NGƠ ANH TUẤN PHÙNG THỊ QUỲNH PHẠM TRỌNG HOAN MSV: 1381510142 MSV: 1381510176 MSV: 1381510140 MSV: 1381510179 MSV: 1381510165 MSV: 1381510127 Lesson 6: Radio Task 1: - Light bulb Televison Oven Telephone Heater Task 2: Table Surface wave Frequencies Low frequencies Travels Along the ground, following the curvature of the earth’s surface Range 1500km at low frequencies (long waves) Difficulties It’s limited mainly by the extent to which energy is absorbed from it by the ground Task 3: Table 2: Sky wave Space wave Frequencies Typically 30 MHz VHF, UHF Travels Skyward Line of sight Range About 80 km above the earth to 500 km Up to 150 km Difficulties The critical frequencies varies with the time of day and the seasons Intervening obstacles such as hills, buildings, or trees Task 4: 12345- a: transmitting aerial e: surface wave d: space wave c: sky wave b: receiving aerial Task 5: When the switch is closed, current flows through the primary of the transformer On trisking a plane, the radar signal is reflected On discharging quickly, a cell may become hot When reciving signal from the remote control, the TV follows your instructions When the radar receiver receives the reflected signal, the signal is compared with the transmitted signal When choosing a coures in the electronics, you think carefully about your future On striking a hight building, microwave signals are deflected When making a recording, you should ensure the recording levels are satisfactory When detecting an intruder, the alarm triggers an audible warning 10 When the remote control button is pressed, the television set changes channel Task 7: Verb Noun (component) Noun (property) Absorb Absorber Absorbion Attenuate Attenuator Attenuation Communicate Communicator Communication Conduct Condution Conductivity Induct Inductor Induction Modulate Modulator Modulation Reflect Reflector Reflection Resist Resistor Resistance Task 9: AF : audio frequency RF : Radio frequency AM : Amplitude modulated FM : Frequency modulated Task 10: 1234- D: FM carrier C: AM carrier B: AF signal A: RF carrier Task 11 : Component Function Aerial Receives weak signals RF tuner Selects the required RF wave RF amplifier Amplifies the RF wave Detector Separates the audio modulation from the RF carrier wave AF amplifier Amplifies the audio signal Loudspeaker Converts the audio signal into sound Task 12 : - Firstly , the aerial receives weak signal Next , the RF tuner selects the required RF wave from the aerial Following that , the selected RF wave is amplified by the RF amplifier and then passed to the detector , which separates the audio modulation from the RF carrier wave After that , the audio frequency amplifier amplifies the audio signal to make it strong enough to drive the loudspeaker Finally , the loudspeaker converts the audio signal into sound Coppyright belong to Nhom