Agilent Technologies E1439 manual Xfers Sequence

Agilent E1439 Programmer's Reference

Functions listed alphabetically

	data		transfer	xfers1	sequence2
data type	resolution	port	width
real	12 bit	Fiber	32 bit	1/2	R0[11:0] Z4R1[11:0] Z4
					R2[11:0] Z4R3[11:0] Z4,...
complex	12 bit	Fiber	32 bit	1	R0[11:0] Z4Q0[11:0] Z4
					R1[11:0] Z4Q1[11:0] Z4 ...
real	24 bit	Fiber	32 bit	1	R0[23:0] Z8
					R1[23:0] Z8 ...
complex	24 bit	Fiber	32 bit	2	R0[23:0] Z8
					Q0[23:0] Z8 ...
					R1[23:0] Z8 ...

1.That is, transfers required per measurement. A fraction indicates multi- ple samples per transfer.

2.Sequence Notation:

R = real number transfer; Q = imaginary number transfer; Z4 = 4 zero pad bits; Z8 = 8 zero pad bits (in the LSBs). Subscript denotes the sample number. Bracketed indices show which sample bits are contained in the transfer, MSB first. A vertical bar denotes bit-wise concatenation. Exam- ple: For a 12-bit sample sent to the LBUS, R0[11:4] indicates the 8 MSBs of the sample are transferred in the first byte. Then R0[3:0] Z4 indicates the 4 LSBs of the sample are padded with 4 zero bits and transferred in the second byte.

The maximum rate at which data may be transferred to memory is determined by the ADC clock rate: MaxBytes/s = 1.5 × (ADC clock rate). Divide MaxBytes/s by 1.5 to get the 12-bit sample rate, and by 3 to get the 24-bit sample rate.

A limitation also applies to 32-bit, complex data transfers. Because this type of transfer cannot be made at the full sample rate, a level of decimation must be added in order to reduce the sample rate.

The following table summarizes the relationship between data parameter combinations, decimation, filter bandwidth, precision, and whether the combination permits block or continuous measurements:

Note	Continuous mode is only limited by maximum transfer rate of the selected interface.
			sample rate	BW fs=100
decimate		filterBW			12b real	24b real	12b complex	24b complex
			(Msamples/s)	MHz
n/a		0	100	40	b
1		1	50	20	b,d		b
0		2	50	10	b,d		b
1		2	25	10	b,c,d	b,d	b,d	b
0		3	25	5	b,c,d	b,d	b,d	b
1		3	12.5	5	b,c,d	b,c,d	b,c,d	b,d

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