1. Video signal amplitude:
The standard video signal amplitude is 1Vp-p, consisting of two test metrics:
1) White clip level (video level): 700 mV
2) Synchronous pulse amplitude: 300 mV
Figure 1: Video Signal
The Impact of Amplitude on Video:
l Synchronization amplitude: Exceeding the specified value can cause image distortion, even making the displayed image unviewable.
l White bar level: Exceeding the target value will result in images that are either too bright or too dark.
2. Brightness Nonlinearity
The linearity of the variation from the blanking level (black level) to the white level.
A step signal with 5-level amplitude (140 mV per level) is passed through the channel under test, and the maximum difference between the corresponding step amplitude values is calculated.
Figure 2: Nonlinear Brightness Calculation
The Impact of Brightness Nonlinearity on Video:
l The image loses grayscale, resulting in reduced tonal levels.
l Resolution is reduced, leading to color saturation distortion (since the chrominance signal is overlaid on the luminance signal).
3. K-factor
Image damage is measured by evaluating various waveform distortions based on the visual characteristics of the human eye—specifically, these distortions refer to short-term waveform distortions.
Generally, "2T sine squared wave distortion" (K-2T) is used as the test metric.
Figure 3: 2T Pulse                                                                                               
Figure 4: K-2T Calculation
The impact of the K-factor on video:
Leading to multiple outlines in the image, causing ghosting and reducing clarity.
4. Differential Gain (DG):
Color signal amplitude distortion caused by variations in the luminance signal amplitude.
The maximum difference between the chroma amplitude values at each step is calculated after the 5-level stepped signal with chroma modulation passes through the channel under test.
Figure 5: Five-Step Modulation of the DG Test Signal

Figure 6: Micro-Differential Gain (DG) Calculation
The Impact of Differential Gain (DG) on Video
l Color saturation distortion under different lighting conditions can affect the overall color appearance. For example: when wearing a bright red outfit and moving from a dimly lit area into a brighter one, the vibrant red may appear deeper or lighter.
5. Differential Phase (DP):
Chromatic signal phase distortion caused by variations in the amplitude of the luminance signal.
After the 5-level stepped signal with chroma modulation passes through the channel under test, the phase difference between the phase angle of the chroma subcarrier at each step and the phase angle of the subcarrier signal at the blanking level is calculated; a leading phase indicates a positive value.
The test signal for DP is the same as that for DG.
The Impact of Differential Phase (DP) on Video
In different lighting conditions, hues become distorted, affecting the overall color perception. For example: when a bright red garment moves from a dimly lit area into a well-lit one, it may appear more yellowish or even slightly purplish.
6. Chrominance/Brightness Gain Difference
A test signal with specified luminance and chrominance component amplitudes is passed through the channel under test. The change in the ratio of luminance to chrominance component amplitudes at the output is referred to as the chrominance-to-luminance gain difference.
Figure 7, 20T Pulse                                          
Figure 8: Calculation of Chrominance/Brightness Gain Difference
The Impact of Chroma/Brightness Gain Difference on Video
Color/brightness gain differences can affect image saturation, leading to distortion. For example: - A negative gain difference causes colors to appear washed out, dull, and gives people a lackluster or unhealthy appearance. - A positive gain difference results in overly saturated colors and poorly defined outlines, resembling the look of a child’s coloring book—lacking realism altogether.
7. Chrominance/Luminance Delay Difference
Pass a test signal with specified luminance and chrominance component amplitudes through the channel under test, and measure the time-domain difference between the corresponding portions of the modulated color waveforms in the luminance and chrominance components. Note: A positive value indicates that the chrominance component delay exceeds the luminance component delay.
The test signal has the same chroma/luminance gain difference.

Figure 9: Calculation of Chrominance/Brightness Delay Difference
The Impact of Chroma/Luminance Delay on Video
Color registration is inaccurate, resulting in colored fringing along the horizontal direction—something the human eye is particularly sensitive to.
8. Frequency Response Characteristic
The gain variation—measured in dB—between the channel input and output relative to a reference frequency point, across the frequency range from the field frequency (low frequency) up to the system’s nominal cutoff frequency (high frequency). The test signal used is a MultiBurst signal, consisting of a MultiBurst Flag combined with six sets of test sine waves at frequencies of 0.5, 1, 2, 4, 4.8, and 5.8 MHz.
Figure 10: MultiBurst Test Signal
The Impact of Frequency Response on Video
Impact on image clarity: If the high-frequency components are heavily attenuated, image details become faint, and edge contours lose their sharpness.