Showing posts with label Signal. Show all posts
Showing posts with label Signal. Show all posts

Friday, 9 October 2015

How a Live TV Signal was sent from Moon ?


Live television was transmitted from the moon to 3 grounds stations, two in Australia and one in California. The signal was converted to a standard broadcast signal and then sent to Houston, via, satellite, landline or microwave antenna. These graphics show the path of the television feed.
Bottom line is, the video was transmitted to one of the large dishes that the DSN uses, and then re-broadcast to the world using standard worldwide broadcasting methods. Specifically, a format was used called slow scan, which according to Wikipedia:

The SSTV system used in NASA's early Apollo missions transferred ten frames per second with a resolution of 320 frame lines using less bandwidth than a normal TV transmission.

Wednesday, 30 September 2015

How memory Card Works in your devices ? what is principle of operation?

Above picture shows the pin out of a memory card which we use in our digital devices. here is a short points about the concept of memory card.
Pin no 1- named as DATA2 but it sends data signal 1
pin no 2- named as DATA3 but it sends data signal 2
pin no 3- CMD I/O means sends commands for Input and output .
pin no 4- named as GND and supplies ground or negative voltage to this component.
pin no 5-named as VDD and supplies positive voltage to this component
pin no 6- Named as CLK and provides clock signal to card to execute the instruction to the card for output
pin no 7- named as GND and supplies negative voltage
pin no 8- Named as DATA0 and provides path for data signal 0
pin no 9- Named as DATA1 and provides path for the Data singal 1