Analog Recording enables you to record with respect to

Screen Co-ordinates.

Low Level Recording enable you to record on any object with

repect to window.

2nd answer

Analog Recording, a single recorded statement is created,

so that we cannot edit recorded statements.

Low-Level Recording, statements are generated according to

operation you do on that object. Each statement starts

with "Window". Here we can edit the recorded statements.

There are some differences between Analog and Low-Level 
Recording modes:
1. Analog mode is useful for recording operations that 
cannot be recorded at the level of an object, for example, 
recording a signature.
Low-Level recording mode enables you to record on any 
object in your application, whether or not QTP recognizes 
the specific object or the specific operation.

2. In analog recording mode, the exact mouse movement and 
keyboard operations are important. Which means that if the 
application is moved to some another place in your desktop 
the test may fail.
You can also use low-level recording if the exact 
coordinates of the object(not the mouse movements) are 
important for your test.

3. A single statement is generated if you working in analog 
mode. Here it records all operations in a single file, and 
just calls to that file. Here we cannot edit the steps in 
analog mode.
For each operation seperate statement will be created in 
Low-level recording mode.

analog;it is used 2 capturing the userr movements across 
the screen

or it records the operation performed on bitmap  

low level;it records the operation of mouse n keyboard 
based window coordinates ,it recognises every window as 
object

in analog we can capture the digital signature 
but that is not posible wit lowlevel