Agilent Technologies N5183A MXG - Manual (Page 323)

Agilent N518xA, E8663B, E44x8C, and E82x7D Signal Generators Programming Guide 313
Creating and Downloading User-Data Files
Pattern RAM (PRAM) Data Downloads (E4438C and E8267D)
PRAM File Size
Because volatile memory resides on the baseband generator (BBG), the maximum PRAM file size
depends on the installed baseband generator option, as shown in
Table 8- 7 .
The maximum PRAM user file size in the table above refers to the maximum number of payload bits.
After downloading, the signal generator translates each downloaded payload bit into a 32- bit word:
• 1 downloaded payload bit
• 7 downloaded control bits as shown in Table 8- 5 on page 310
• 24 bits added by the signal generator
The following table shows the maximum file size after the signal generator has translated the
maximum number of payload bits into 32- bit words.
To properly size a PRAM file, you must determine the file size after the 32- bit translation process.
The signal generator measures a PRAM file size in units of bytes; each 32- bit word equals 4 bytes.
Determining the File Size
The following example shows how to calculate a downloaded file size using a PRAM file that contains
89 bytes (payload bits plus 7 control bits per payload bit):
89 bytes + [(89
× 24 bits) / 8] = 356 bytes
Because the file downloads one fourth of the translated 32- bit word, another method to calculate the
file size is to multiply the downloaded file size by four:
89 bytes
× 4 = 356 bytes
See also “Signal Generator Memory” on page 281 and “Checking Available Memory” on page 285 .
Table 8-7 Maximum PRAM User File Size (Payload Bits Only)
Modulation
Format
Baseband Generator Option
001, 601 002 602
Custom
TDMA
8 Mbits a
a. File size with no other files residing in volatile memory.
32 Mbits a 64 Mbits a
Table 8-8 Maximum File Size After Downloading
Modulation
Format
Baseband Generator Option
001, 601 002 602
Custom
TDMA
32 MBytes a
a. File size with no other files residing in volatile memory.
128 MBytes a 256 MBytes a