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
8
−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.
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