User guide

is an odd number of bits long, it is loaded into the RAM 512 times. Because of the
restricted memory space, there are also restrictions to the pattern lengths.
For example, a user pattern that is 256,001bit bit long would have to be loaded into
the RAM 512 times to reach the 512-bit boundary. Such a pattern would occupy
more than 128 Mbits in the RAM.
The Serial BERT handles such patterns by rounding them off to the nearest length
that would fit in the memory. For the above example, the length would be rounded
off to 256,000 bits. This rounding-off factor is known as the pattern's resolution.
The following table lists all pattern resolutions.
Table 5
Pattern length (standard) Pattern length (alternate) Resolution
≤ 64 kbit ≤ 32 kbit
1 bit
> 64 kbit > 32 kbit 2 bit
> 128 kbit > 64 kbit 4 bit
> 256 kbit > 128 kbit 8 bit
> 512 kbit > 256 kbit 16 bit
> 1 Mbit > 512 kbit 32 bit
> 2 Mbit > 1 Mbit 64 bit
> 4 Mbit > 2 Mbit 128 bit
> 8 Mbit > 4 Mbit 256 bit
> 16 Mbit > 8 Mbit 512 bit
N O T E
The above table is not valid for 8B/10B Comparison mode. In 8B/10B Comparison
mode, the error message is generated if a pattern occupies more than 32 Mbits after
reaching 512-bit boundary.
3 Setting up Patterns
68 Agilent J-BERT N4903B High-Performance Serial BERT