Agilent Technologies E1439 User Manual page 104

Agilent E1439 Programmer's Reference
Functions listed alphabetically
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.
decimate
n/a
1
0
1
0
1
94
data
data type resolution
real 12 bit
complex 12 bit
real 24 bit
complex 24 bit
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.
sample rate BW fs=100
filterBW
(Msamples/s)
0 100
1 50
2 50
2 25
3 25
3 12.5
transfer
port width
Fiber 32 bit
Fiber 32 bit
Fiber 32 bit
Fiber 32 bit
12b real 24b real
MHz
40 b
20 b,d
10 b,d
10 b,c,d
5 b,c,d
5 b,c,d b,c,d
1 2
xfers sequence
1/2 R [11:0] |Z4|R [11:0] |Z4
0 1
R [11:0] |Z4|R [11:0] |Z4,...
2 3
1 R [11:0] |Z4|Q [11:0] |Z4
0 0
R [11:0] |Z4|Q [11:0] |Z4 ...
1 1
1 R [23:0] |Z8
0
R [23:0] |Z8 ...
1
2 R [23:0] |Z8
0
Q [23:0] |Z8 ...
0
R [23:0] |Z8 ...
1
12b complex 24b complex
b
b
b,d b,d
b,d b,d
b,c,d
b
b
b,d