Agilent Technologies E1439 manual Append

Using the Agilent E1439

Fiber Optic Interface

	Append
	The Append fiber mode copies optical data from its fiber receiver to its fiber transmitter and
	appends its own filtered ADC data. This mode is required in an optical fiber append chain. For
	the first module in an append chain, set the fiber mode to Generate, BOF to ON, and Epoch
	Generate to ON. The module generates data epochs in the standard fashion and a BOF is sent after
	each epoch. For all modules after the first, set fiber mode to Append, BOF to ON, and Epoch
	Generate to ON. Each module copies received data to its transmitter output until a BOF is
	received. The module then sends one epoch of filtered data from its ADC (if at least one block is
	available), followed by a BOF.
	In block data mode, the data from a single trigger is transmitted. Subsequent triggers should not
	be generated faster than the data can be transmitted.
	In continuous data mode, the generated data must not exceed the available fiber bandwidth,
	allowing the data to be merged without data loss from a FIFO overrun. Therefore, you must
	reduce the generated sample rate using either an external sample clock operating at a slower rate
	or data decimation. If you use an external sample clock operating at a slower rate, epoch size must
	be 1024 bytes (a larger epoch size causes a FIFO overrun resulting in a loss of data, and a smaller
	epoch size increases overhead reducing the available bandwidth). The available bandwidth is then
	about 101 MBytes/second or 238 MBytes/second. If you use data decimation, an epoch size of
	approximately 2048 bytes provides the maximum available bandwidth.
Note	Epoch size and block size must be equal (in bytes). Since block size is in samples, you can
	multiply block size by the number of bytes per sample to determine the equivalent epoch size.
	Conversely, you can divide the epoch size by the number of bytes per sample to determine the
	equivalent block size. Real 12-bit data contains 2 bytes per sample, complex 12-bit data and real
	24-bit data contains 4 bytes per sample, and complex 24-bit data contains 8 bytes per sample.

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