Analog Cameras

Analog cameras output a video signal in an analog format. The horizontal sync (HSYNC) pulse identifies the beginning of each line; multiple lines make up a field. An additional pulse, called the vertical sync (VSYNC), identifies the beginning of a field. For most traditional analog cameras, the odd and even fields are interlaced to increase the perceived image update rate. Two fields make up one frame. Some higher-end cameras expose the entire image at once. The following figure illustrates the analog output of a video signal.

The black level is a reference voltage for measuring pixel intensities. Low voltages typically indicate darker pixels, while higher voltages result in lighter pixels.