REV. B
AD73360
–10–
TERMINOLOGY
Absolute Gain
Absolute gain is a measure of converter gain for a known signal.
Absolute gain is measured (differentially) with a 1 kHz sine
wave at 0 dBm0 for each ADC. The absolute gain specification
is used for gain tracking error specification.
Crosstalk
Crosstalk is due to coupling of signals from a given channel to
an adjacent channel. It is defined as the ratio of the amplitude of
the coupled signal to the amplitude of the input signal. Crosstalk
is expressed in dB.
Gain Tracking Error
Gain tracking error measures changes in converter output for
different signal levels relative to an absolute signal level. The
absolute signal level is 0 dBm0 (equal to absolute gain) at 1 kHz
for each ADC. Gain tracking error at 0 dBm0 (ADC) is 0 dB by
definition.
Group Delay
Group Delay is defined as the derivative of radian phase with
respect to radian frequency, dø(f)/df. Group delay is a measure
of average delay of a system as a function of frequency. A linear
system with a constant group delay has a linear phase response.
The deviation of group delay from a constant indicates the de-
gree of nonlinear phase response of the system.
Idle Channel Noise
Idle channel noise is defined as the total signal energy measured
at the output of the device when the input is grounded (mea-
sured in the frequency range 0 Hz–4 kHz).
Intermodulation Distortion
With inputs consisting of sine waves at two frequencies, fa and
fb, any active device with nonlinearities will create distortion
products at sum and difference frequencies of mfa ± nfb where
m, n = 0, 1, 2, 3, etc. Intermodulation terms are those for which
neither m nor n are equal to zero. For final testing, the second
order terms include (fa + fb) and (fa – fb), while the third order
terms include (2fa + fb), (2fa – fb), (fa + 2fb) and (fa – 2fb).
Power Supply Rejection
Power supply rejection measures the susceptibility of a device to
noise on the power supply. Power supply rejection is measured
by modulating the power supply with a sine wave and measuring
the noise at the output (relative to 0 dB).
Sample Rate
The sample rate is the rate at which each ADC updates its out-
put register. It is set relative to the DMCLK and the program-
mable sample rate setting.
SNR + THD
Signal-to-noise ratio plus harmonic distortion is defined to be
the ratio of the rms value of the measured input signal to the
rms sum of all other spectral components in a given frequency
range, including harmonics but excluding dc.
ABBREVIATIONS
ADC Analog-to-Digital Converter.
BW Bandwidth.
CRx A Control Register where x is a placeholder for
an alphabetic character (A–E). There are eight
read/write control registers on the AD73360—
designated CRA through CRE.
CRx:n A bit position, where n is a placeholder for a
numeric character (0–7), within a control regis-
ter; where x is a placeholder for an alphabetic
character (A–E). Position 7 represents the MSB
and Position 0 represents the LSB.
DMCLK Device (Internal) Master Clock. This is the
internal master clock resulting from the external
master clock (MCLK) being divided by the on-
chip master clock divider.
FSLB Frame Sync Loop-Back—where the SDOFS of
the final device in a cascade is connected to the
RFS and TFS of the DSP and the SDIFS of first
device in the cascade. Data input and output
occur simultaneously. In the case of nonFSLB,
SDOFS and SDO are connected to the Rx Port
of the DSP while SDIFS and SDI are connected
to the Tx Port.
PGA Programmable Gain Amplifier.
SC Switched Capacitor.
SNR Signal-to-Noise Ratio.
SPORT Serial Port.
THD Total Harmonic Distortion.
VBW Voice Bandwidth.
