The terms t_P_LH and t_P_HL​​ refer to the propagation delays associated with the low-to-high and high-to-low transitions in a digital signal. These delays are essential in digital systems and are measured with respect to the voltage levels.

(Low-to-High Propagation Delay):

• This is the time it takes for a signal to transition from a low voltage level to a high voltage level.
• It's measured as the time difference between the 50% voltage points on the rising edge of the input and output signals.

(High-to-Low Propagation Delay):

• This is the time it takes for a signal to transition from a high voltage level to a low voltage level.
• It's measured as the time difference between the 50% voltage points on the falling edge of the input and output signals.

Key point is to measure the time difference between the 50% voltage points on the rising edges of the input and output signals.

1. Volts/Div (Volts per Division):

   • It represents the vertical scaling on the oscilloscope.
   • This value indicates the voltage range represented by each vertical division on the display.
   • For example, if the setting is 1 Volt/Div, each vertical division on the screen represents 1 volt.

2. Sec/Div (Seconds per Division):

   • It represents the horizontal scaling on the oscilloscope.
   • This value indicates the time duration represented by each horizontal division on the display.
   • For example, if the setting is 1 Sec/Div, each horizontal division on the screen represents 1 second.

1. Volts/Div（每格电压）：

   • 它代表示示波器的垂直缩放。
   • 该数值表示屏幕上每个垂直刻度所代表的电压范围。
   • 例如，如果设置为1 Volt/Div，屏幕上每个垂直刻度代表1伏特。

2. Sec/Div（每格秒）：

   • 它代表示示波器的水平缩放。
   • 该数值表示屏幕上每个水平刻度所代表的时间跨度。
   • 例如，如果设置为1 Sec/Div，屏幕上每个水平刻度代表1秒

How to read the criterion?

1. Ch1 2V:

   • It indicates Channel 1 (Ch1) on the oscilloscope.
   • The setting is at 2 volts per division (2V/Div).
   • This means that each vertical division on the display represents a voltage range of 2 volts.

2. Ch2 2V 5ns:

   • It indicates Channel 2 (Ch2) on the oscilloscope.
   • The setting is at 2 volts per division (2V/Div) for the vertical axis.
   • The setting is at 5 nanoseconds per division (5ns/Div) for the horizontal axis.
   • This means that each vertical division represents a voltage range of 2 volts, and each horizontal division represents a time duration of 5 nanoseconds.

In Chinese (简体中文):

1. Ch1 2V:

   • 表示示波器的第1通道（Ch1）。
   • 设置为每格电压为2伏特（2V/Div）。
   • 意味着屏幕上每个垂直刻度代表2伏特的电压范围。

2. Ch2 2V 5ns:

   • 表示示波器的第2通道（Ch2）。
   • 设置为每格电压为2伏特（2V/Div）的垂直轴。
   • 设置为每格时间为5纳秒（5ns/Div）的水平轴。
   • 意味着每个垂直刻度代表2伏特的电压范围，每个水平刻度代表5纳秒的时间跨度。