DVDO VP20 用户手册

 

Parameter 

Carrier Frequency
Unit of Burst Time
Lead In Burst 
"1" Burst Pattern 
"0" Burst Pattern 
Lead Out

 

Decimal Value 

40kHz 
22 cycles of the carrier
341 171 
22 96 
22 24 
22, 1427

 

 
 
0156 00ab 
0016 0060 
0016 0016 
0016 0593

 

Doing the arithmetic we see that this code uses a base time of 550 microseconds. 

The lead in is a unique burst as is the lead out. It is a pulse width modulation system 
where the information is carried in the length of the off time with a fixed duration of on 
time.  The NEC message format is quite a bit more complicated then that of Sony. It is 
always a 32-bit code. Which consists of 16 bits of data and 16 bits of error checking.  
 

The code is divided into four 8-bit fields.  

 

 

 

A device code will be in the range of 0 to 255 or 256 discrete device codes. The 

same is true of the function code. The compliment fields are the 1’s compliment of the 
code they represent. The device code and the device code compliment must add up to 255 
or else there is an error. The same is true of the function code and the function code 
compliment. NEC uses a discrete lead in and a discrete lead out, so the total code length 
will take 34 burst pairs to represent as a Burst Pair Sequence.  
 

The following as an example of a Pioneer IR sequence for the CLD79 Elite Laser 

Disk Player.  

 

 

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