Engineering and Technology

Here is my YouTube video Hindi version about this circuit: This  BH1417  pll fm transmitter includes features like: pre-emphasis, sound limiter, stereo transmission, low pass filter, pll circuit, fm oscillator and rf output buffer. The sound limiter maintains the same audio level so no distorsions occur, the stereo encoder separates the left and right channel enabling stereo transmission, the low pass filter blocks any audio signal above 15 Khz to prevent rf interference and the pll circuit provides a rock solid frequency stability. There are 14 possible transmission frequencies with 200KHz increments selected with a 4-DIP switch. Starts from 88.7 up to 89.9 MHz and 107.7 up to 108.9 MHz. S4 S3 S2 S1 Frequency 1 1 1 1 88.7 MHz 1 1 1 0 88.9 MHz 1 1 0 1 89.1 MHz 1 1 0 0 89.3 MHz 1 0 1 1 89.5 MHz 1 0 1 0 89.7 MHz 1 0 0 1 89.9 MHz 1 = ON, 0 = OFF Simply select transmissi...

Here is my video supporting this article: Description of Home security system: There are several home security systems out there. Different manufacturers use different techniques and topology in their design. Cameras are also very popular for the purpose of security. Main problem with security cameras is to monitor them. They have capability to record the view in DVR hard drive but they could not stop intruder from intrusion. They are just providing the proof after the incident happens. Whereas in most cases we want to stop an intruder from intrusion. for this purpose different types of alarming systems are developed which warns the intruders not to enter in a specific area. also these system are kind of passive systems which needs only power up and they stays in sort of sleeping mode when everything is normal. They activate an alarm at the time of intrusion. They don't normally need to observe. So such systems are better in the way that all the time monitoring is not needed...