AD7011

REV. B

–8–

TERMINOLOGY

Error Vector Magnitude

This is a measure of the rms error vector introduced by the

AD7011 where signal error vector is defined as the rms devia-

tion of a transmitted symbol from its ideal position when filtered

by an Ideal RRC Receive filter, as illustrated in Figure 8.

Gain Matching Between Channels

The is the gain matching between the I and Q outputs, measured

when transmitting all zeros.

Offset Vector Magnitude

This is a measure of the offset vector introduced by the AD7011

as illustrated in Figure 8. The offset vector is calculated so as to

minimize the rms error vector for each of the constellation

points.

Output Signal Range and Different Output Range

The output signal range is the output voltage swing and dc bias

level for each of the analog outputs. The different output range

is the difference between ITx and ITx for the I channel and the

difference between QTx and QTx for the Q Channel.

IS-54 Spurious Power

This is the rms sum of the spurious power measured at multiples

of 30 kHz, in a root raised cosine window of

±16.4 kHz, relative

to twice the rms power in a RRC window in the 0 to 16.4 kHz

band.

Signal Vector Magnitude

This is the radius of the IQ constellation diagram as illustrated

in Figure 8.

Signal to (Noise + Distortion) Ratio

This is the measured ratio of signal to (noise + distortion) at the

output of the transmit I and Q DACs. The signal is the rms

amplitude of the fundamental. Noise is the rms sum of all non-

excluding dc. The ratio is dependent upon the number of

quantization levels in the digitization process; the more levels,

the smaller the quantization noise. The theoretical signal to

(noise distortion) ratio for a sine wave is given by:

SNR = (6.02N + 1.76) dB

where N is the number of bits. Thus for an ideal 10-bit con-

verter, SNR = 61.96 dB.

I

Q

ERROR VECTOR

OFFSET

VECTOR

0,0

SIGNAL VECTOR

Figure 8.