As you can see this is a nonperiodic composite signal in 1s and I know that if the composite signal is nonperiodic, the decomposition gives a combination of sine waves with continuous frequencies.I don't know how to use fourier analysis to decomposite this composite signal into simple sine waves.
Can I just make a quick conclusion to say because the signal completes 4 cycles in one second, so the frequency is 4Hz?
PS: This questions originates from my textbook's description of signal received by an old-fashioned analog black-and-white TV. It says
An example of a nonperiodic composite signal is the signal received by an old-fashioned analog black-and-white TV.A TV screen is made up of pixels with each pixel being either white or black. The screen is scanned 30 times per second.If we assume a resolution of 525 × 700 (525 vertical lines and 700 horizontal lines), we have 367,500 pixels per screen. If we scan the screen 30 times per second, this is 367,500 × 30 = 11,025,000 pixels per second. The worst-case scenario is alternating black and white pixels. In this case, we need to represent one color by the minimum amplitude and the other color by the maximum amplitude. We can send 2 pixels per cycle. Therefore, we need 11,025,000 / 2 = 5,512,500 cycles per second, or Hz. The bandwidth needed is 5.5124 MHz.
So I'm going to simplify this and connect my textbook's description to my original question. Let's say I have a tiny TV that only has 8 pixels. So I am sending the signal in the picture, representing 8 pixels, the high amplitude represents "white" and low amplitude means "black", so the signal in the pictures represents the pixels(from pixel 1 to pixel 8) in the TV should be "wbwwbwww", then according to the textbook, We can send 2 pixels per cycle, Therefore, we need 8 / 2 = 4 cycles per second(4 Hz).