Agilent Technologies N5181A/82A User Manual download pdf (Page 196)

186 Agilent N518xA, E8663B, E44x8C, and E82x7D Signal Generators Programming Guide

Creating and Downloading Waveform Files

Understanding Waveform Data

The maximum value for a single unsigned byte is 255 (11111111 or 2

−1), but you can use multiple

bytes to represent larger values. The following shows two bytes and the resulting integer value:

01101110 10110011= 28339 (decimal value)

The maximum value for two unsigned bytes is 65535. Since binary strings lengthen as the value

increases, it is common to show binary values using hexadecimal (hex) values (base 16), which are

shorter. The value 65535 in hex is FFFF. Hexadecimal consists of the values 0, 1, 2, 3, 4, 5, 6, 7, 8,

9, A, B, C, D, E, and F. In decimal, hex values range from 0 to 15 (F). It takes 4 bits to represent a

single hex value.

For I and Q data, the signal generator uses two bytes to represent an integer value.

LSB and MSB (Bit Order)

Within groups (strings) of bits, we designate the order of the bits by identifying which bit has the

highest value and which has the lowest value by its location in the bit string. The following is an

example of this order.

Little Endian and Big Endian (Byte Order)

When you use multiple bytes (as required for the waveform data), you must identify their order. This

is similar to identifying the order of bits by LSB and MSB. To identify byte order, use the terms little

endian and big endian. These terms are used by designers of computer processors.

1 = 0001 2 = 0010 3 = 0011 4 = 0100 5 = 0101

6 = 0110 7 = 0111 8 = 1000 9 = 1001 A = 1010

B = 1011 C = 1100 D = 1101 E = 1110 F = 1111

Most Significant Bit (MSB) This bit has the highest value (greatest weight) and is located at the far left of the bit

string.

Least Significant Bit (LSB) This bit has the lowest value (bit position zero) and is located at the far right of the

bit string.

Intel is a registered trademark of Intel Corporation.

1 0 1 1 0 1 1 1 1 1 1 0 1 0 0 1

LSB

MSB

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Data

Bit Position

Because we are using 2 bytes of data, the LSB appears in the second byte.

1 2 ... 191 192 193 194 195 196 197 198 199 200 201 ... 365 366

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Agilent Technologies N5181A/82A User Manual Page 196