Patterns 4xCRPAT (hppat05.dat) and 4xCJPAT (hppat06.dat) have been created as 'alternate patterns'. When downloaded into the 71612C this allows pattern A to be used as the required data pattern and pattern B to be transmitted once to de-skew the four XAUI lanes before measuring BER with the chosen data pattern. To transmit pattern B once, first select and download the required pattern by pressing the key from the pattern selection menu. When an 'alternate pattern' is selected and downloaded into the pattern generator the alternate pattern control soft-keys are activated. To manually transmit a single repetition of the de-skew pattern (B) and then to return to the continuous transmission of pattern A, toggle control key to select USR and then key to select ONCE. Having done this the key is active and when pressed inserts one repetition of pattern B in a continuously looping pattern A.
The following description of 802.3ae High Frequency Test Pattern (hppat11.dat) explains in detail how these XAUI test patterns are programmed such that the desired patterns are generated at the four sub-rate outputs of the pattern generator. The construction of the de-skew (alt pattern B) is also described.
802.3ae High frequency test pattern This pattern is intended to be used to test random jitter (RJ) at a BER of 10-12 and also to test the asymmetry of transition times; it is not intended for jitter compliance testing. The pattern generates an alternating one zero pattern on each Agilent 71612C sub-rate output and XAUI input lane 01010101010101….etc. This pattern represents the continual transmission of the D21.5 code-group on each XAUI lane. The high frequency test pattern would be programmed into the 71612C pattern generator as 0000111100001111000011110000…etc.
The ‘alternate pattern’ mode of operation of the 71612C is used to de-skew the XAUI lanes in the ASIC before performing BER measurements on the data pattern. ‘Alternate pattern’ mode divides the custom pattern memory into two banks of 4Mbits. Two equal length patterns may be programmed and then selected synchronously – either manually, or with a TTL control signal, or by GP-IB. Pattern Ap is programmed as described above using the 71612C editor, and pattern Bp is programmed so that the required standard /A/K/ bytes (and/R/ byte if required) are produced at the 71612C sub-rate outputs
High frequency test pattern as programmed as pattern Ap in ‘alternate pattern’ mode:
Pattern Ap 0000111100001111000011110000…
Sub-rate 0,1,2,3 0 1 0 1 0 1 0..
Pattern Bp 0000000011111111111111111111000011110000111111110000000000000000
The sub-rate outputs would output every fourth bit as follows:
0011111010 1100000101 00111110101100000101…
-K28.5 +K28.5 -K28.5 This is the required repeating K28.5 Sync or ‘K’ word taking account of running disparity rules for the 8B/10B transmission code. Positive and negative running disparity is fully explained in section 11 of the Fibre Channel FC-PH document. The tables of valid data characters and valid special characters may also be found in section 11 of this document.
This K word is repeated 16 times (ending at bit 639) followed by one repetition of the align word – the A word (K28.3).
Following running disparity rules the A word (K28.3) is programmed into pattern Bp from bit 640 as:
At the sub-rate outputs every fourth bit would be transmitted as:
0011110011 1100000101 00111110101 etc
-K28.3 +K28.5 -K28.5 etc The 16 x K28.5 word + 1 x K28.3 word is repeated N times; in this case N=2, and the repeated pattern ends with bit 1359. Then pattern Bp is programmed such that a valid special character is generated on lane (sub-rate) 0 as a ‘start of data’ character – for example –K27.7.
Pattern Bp from bit 1280: