# Determine line rate and frame rate of a system

I have as a homework to determine the line rate and frame rate for a system described above:

Heigh of monitor:             40cm
Screen Aspect Ratio:          16:9
Pixel Aspect Ratio:           4:3
Progressive scan
Viewing distance from screen: 0.6m
Active line period:           15μs
Horizontal Blanking:          5μs
Vertical blanking lines:      20


I search for the definitions in order to understand the system:

Line rate: It indicates the actual speed with which the bits are sent onto the wire

Frame rate: frequency at which an imaging device produces unique images(frames)

Progressive video: is the method by which all lines (whole frame) are captured at the same instant, representing a single moment in time

The screen aspect ratio is width divided by height, and the same for the pixel aspect ratio.

Horizontal blanking interval refers to a part of the process of displaying images on a computer monitor or television screen via raster scanning. CRT screens display images by moving beams of electrons very quickly across the screen. Once the beam of the monitor has reached the edge of the screen, the beam is switched off, and the deflection circuit voltages (or currents) are returned to the values they had for the other edge of the screen; this would have the effect of retracing the screen in the opposite direction, so the beam is turned off during this time.

Vertical blanking interval is an interval of time between the last line of a given frame and the beginning of the next frame, during which the incoming data stream is not displayed on a CRT screen. It is the time interval allowed for the analog TV electron gun beam to move from the bottom of the current frame to the top of the next one as it scans images. This requires the last 45 lines of each 525-line frame.

My problem is that i cant find a proper way to calculate the line rate or frame rate from the above. I didn't find any equation or a guide. Can someone help me or point me a tutorial? I assume that the line rate has something to do with the horizontal blanking and vertical blanking because the electrons that need to provide through the wire, but still i need an equation.

• I don't think there's enough information to answer this. You probably need at least one other piece of information e.g. screen resolution or broadcast standard. May 12, 2013 at 20:23
• Because i have to create a new standard with a suitable line rate and frame rate, then if i choose a screen resolution what calculations i need to do to find these values? May 13, 2013 at 7:05
• Frame rate and resolution are straight forward. For example 25p progressive is 25 frames per second. But the line rate? How i can find the line rate if i assume that the resolution is 25p? May 13, 2013 at 7:14
• I think your definition of line rate is wrong. Typical definition should be "number of lines per second" not the "number of bits per second". It's easy to answer the first, impossible to answer the second (unless there is more info) May 13, 2013 at 17:12
• Yes, of course. Just calculate the length of line in terms of time. The inverse is the line rate. May 14, 2013 at 0:57