(It's done in practice in high-end AM receivers, by phase locking to the carrier and using the result for the local oscillator - it's called exalted-carrier demodulation). You can, in theory, demodulate AM by downconversion, but you need to be synchronized to the carrier frequency to do it, or you get nasty fading. You could down-convert to baseband and then demodulate there, but you'd still be demodulating. Take FM, convert it to baseband, and the result is a nasty-sounding mess. You cannot demodulate FM by downconversion, at all. So you can "demodulate" SSB by downconversion. The actual process doesn't necessarily happen that way, but the result is the same. Single-sideband modulation is, essentially, the process of taking one half of a baseband signal (either the positive frequency components or the negative ones) and up-converting the result. Demodulating conventional broadcast AM is different than demodulating FM, and both are different from demodulating single sideband. Demodulation is specific to the type of modulation used. Not just for this question - for all of the ones you've been answering, and for the ones that you haven't thought to ask.ĭown- (and up-) conversion is a specific operation, independent of the type of modulation. To indicate a stop, bend your arm at the elbow with your hand and forearm pointing toward the ground, and your palm open and facing backward.īy using turn signals or hand signals, you will reduce your chances of traffic collisions and traffic tickets, and ensure the safety of all road users.Unless they've really gone downhill in the last ten years, you want to get an ARRL Handbook (or the GBRS Manual, if you're in England). When turning right, bend your arm at the elbow with your hand pointing upward. When turning left, extend your arm straight outwards. To make a hand signal, roll down your driver side window and extend your arm outside the car. You only need to use hand signals to indicate a turn or stop if the signal lights or brake lights on your car are not working, or if for some other reason another driver or pedestrian may not be able to see your turn signals or brake lights. Using Hand Signals for Turning and Stopping When driving on the highway and indicating an exit, lane change, or overtake, start your indicator lights approximately 900 feet before you make the change. Put your turn signal on approximately 100 feet before you reach the intersection. When you turn left or right at an intersection, you should be in the lane closest to the direction you are turning in. There may be traffic you cannot see, and using them should be a habit in every situation. Merging with traffic when entering a roadwayĮven if there is no other vehicles or pedestrians in the area, you should use your turn signals. Making a left or right-hand turn at an intersectionĮntering a driveway or parking lot on either side of the road Use your turn signals or a hand signal when doing any of the following: Brake lights come on automatically when you step on the brakes. By pushing the lever up, you activate the signals on the left side of the vehicle for a left-hand turn. By pulling the lever down, you activate the signals on the right side of the car to indicate a right-hand turn. The turn signals on most vehicles are located on a short lever attached to the side of the steering wheel column. Knowing the right way to use turn signals need not be a burden using them should be an automatic habit, so you don’t even have to think about it when you are driving. The law also specifies the distance before your intended maneuver that you must activate them. Using your turn signals is not only the safe thing to do, but it’s also legally required. An increasing number of people are failing to use their indicators, and this is causing a growing number of accidents. The turn signals on your car are an essential safety device that allows you to communicate your intentions to other drivers.
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