Protocol Settings
R&S
®
EX-IQ-BOX
179
User Manual 1409.5570.32 ─ 05
"2's Complement 9E2"
Format the signal in two's-complement variant 9E2.
9E2 encoding format is used in mobile base stations to extend the
dynamic range of I and Q, while reducing the needed amount of bits.
The coding is 9E2 with 9 bits mantissa and 2 bits exponent, that are
shared from I and Q, as shown in the figure:
I
1
Q
1
I
2
Q
2
I
0
Q
0
I
3
Q
3
I
4
Q
4
I
5
Q
5
I
6
Q
6
I
7
Q
7
I
8
Q
8
I
9
Q
9
Common
exponent
Q mantissa
I mantissa
Fig. 7-69: 2's complement 9E2
The I and Q samples of the 2's complement 9E2 are calculated with the
formulas:
I sample 10 bits = 9 bits ma 1 bit, bit_0 exponent
0
0
2
9
8
7
0
1
2
2
2
I
Q
i
i
i
I
I
I
Q sample 10 bits: 9 bits Q ma 1 bit, bit_1 exponent
0
0
2
9
8
7
0
1
2
2
2
I
Q
i
i
i
Q
Q
Q
Remote command:
I/Q Resolution
Set the I/Q resolution in bits. The resolution is valid for both, the I and the Q values. I.e,
if you set the resolution to 16 bits, the sample rate is 32 bits wide, composed of 16-bit I
and 16-bit Q.
Remote command:
Gain
Set a gain value for the I/Q signal. Positive values lead to a digital signal amplification,
and negative values correspond to a digital signal attenuation. A gain value of 0
dB results
in an unchanged level of the I/Q signal. By default, the value is set to 0
dB.
Remote command:
CPRI
Summary of Contents for EX-IQ-BOX
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