[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:03.28,Default,,0000,0000,0000,,>> Hello, this is Dr. Cynthia Furse\Nof the University of Utah.
Dialogue: 0,0:00:03.28,0:00:05.70,Default,,0000,0000,0000,,Today, I would like to show\Nyou how capacitors and
Dialogue: 0,0:00:05.70,0:00:08.26,Default,,0000,0000,0000,,inductors are used in\Nthis microwave circuit.
Dialogue: 0,0:00:08.26,0:00:12.33,Default,,0000,0000,0000,,This is the receiver for\Na wireless local area network,
Dialogue: 0,0:00:12.33,0:00:15.92,Default,,0000,0000,0000,,that's able to transmit signals\Nfrom one computer to the other.
Dialogue: 0,0:00:15.92,0:00:17.86,Default,,0000,0000,0000,,Computers talking digital code,
Dialogue: 0,0:00:17.86,0:00:20.43,Default,,0000,0000,0000,,they use ones and zeros\Nto represent letters,
Dialogue: 0,0:00:20.43,0:00:21.99,Default,,0000,0000,0000,,numbers and so on.
Dialogue: 0,0:00:21.99,0:00:25.23,Default,,0000,0000,0000,,But we can't transmit a one\Nor a zero through the air.
Dialogue: 0,0:00:25.23,0:00:29.42,Default,,0000,0000,0000,,Instead, this circuit uses two frequencies\Nto represent the one and the zero.
Dialogue: 0,0:00:29.42,0:00:31.66,Default,,0000,0000,0000,,The zero is 2.4 gigahertz,
Dialogue: 0,0:00:31.66,0:00:34.05,Default,,0000,0000,0000,,and one is 2.6 gigahertz.
Dialogue: 0,0:00:34.05,0:00:36.12,Default,,0000,0000,0000,,So we transmit one or the other of
Dialogue: 0,0:00:36.12,0:00:39.34,Default,,0000,0000,0000,,those frequencies representing\Nthe one or the zero.
Dialogue: 0,0:00:39.34,0:00:41.66,Default,,0000,0000,0000,,Now here's how this circuit works.
Dialogue: 0,0:00:41.66,0:00:44.24,Default,,0000,0000,0000,,First, you start with the antenna.
Dialogue: 0,0:00:44.24,0:00:47.08,Default,,0000,0000,0000,,The antenna is going to receive the signal,
Dialogue: 0,0:00:47.08,0:00:49.85,Default,,0000,0000,0000,,transmit it to an amplifier that's going to
Dialogue: 0,0:00:49.85,0:00:53.32,Default,,0000,0000,0000,,amplify the signal because it's too\Nlittle when it comes in at the antenna.
Dialogue: 0,0:00:53.32,0:00:56.76,Default,,0000,0000,0000,,It's then going to split\Nthat signal into two equal parts.
Dialogue: 0,0:00:56.76,0:01:01.86,Default,,0000,0000,0000,,We don't know if it's a 2.4 or 2.6\Ngigahertz signal at this point,
Dialogue: 0,0:01:01.86,0:01:04.28,Default,,0000,0000,0000,,but the signal is going to end up here
Dialogue: 0,0:01:04.28,0:01:06.83,Default,,0000,0000,0000,,and here when it passes\Nthrough this splitter.
Dialogue: 0,0:01:06.83,0:01:09.62,Default,,0000,0000,0000,,Now we have two band pass filters,
Dialogue: 0,0:01:09.62,0:01:14.14,Default,,0000,0000,0000,,one passes 2.4 gigahertz\Nand the other passes 2.6,
Dialogue: 0,0:01:14.14,0:01:17.75,Default,,0000,0000,0000,,and those are going to tell us which\Nof the two frequencies we have.
Dialogue: 0,0:01:17.75,0:01:20.54,Default,,0000,0000,0000,,There's going to be\Nan output voltage either here,
Dialogue: 0,0:01:20.54,0:01:22.49,Default,,0000,0000,0000,,if it's 2.4 or here,
Dialogue: 0,0:01:22.49,0:01:24.52,Default,,0000,0000,0000,,if it's 2.6 gigahertz.
Dialogue: 0,0:01:24.52,0:01:27.95,Default,,0000,0000,0000,,Then, it's going to come\Ninto a diode detector.
Dialogue: 0,0:01:27.95,0:01:29.69,Default,,0000,0000,0000,,The way a diode detector works,
Dialogue: 0,0:01:29.69,0:01:31.67,Default,,0000,0000,0000,,is it makes it so only the positive part
Dialogue: 0,0:01:31.67,0:01:33.48,Default,,0000,0000,0000,,of the signal can be transmitted through,
Dialogue: 0,0:01:33.48,0:01:37.50,Default,,0000,0000,0000,,and then it averages it to be able\Nto see which of these has a voltage.
Dialogue: 0,0:01:37.50,0:01:39.05,Default,,0000,0000,0000,,So by the time we get to the end,
Dialogue: 0,0:01:39.05,0:01:41.24,Default,,0000,0000,0000,,there's going to be a DC voltage here,
Dialogue: 0,0:01:41.24,0:01:43.96,Default,,0000,0000,0000,,or a DC voltage there but not both.
Dialogue: 0,0:01:43.96,0:01:46.43,Default,,0000,0000,0000,,That will tell us if it's a zero or a one,
Dialogue: 0,0:01:46.43,0:01:48.74,Default,,0000,0000,0000,,and then that can be\Nbrought into the computer.