ADE7761B

Rev. 0 | Page 10 of 24

TERMINOLOGY

Measurement Error

The error associated with the energy measurement made by the

ADE7761B is defined by

%

100

×

⎟

⎟

⎠

⎞

⎜

⎜

⎝

⎛

−

=

Energy

True

Energy

True

ADE7761B

by

Registered

Energy

Error

Percentage

Phase Error Between Channels

The high-pass filter (HPF) in the current channel has a phase

lead response. To offset this phase response and equalize the

phase response among channels, a phase correction network is

also placed in the current channel. The phase correction network

ensures a phase match between the current channels and the

voltage channels to within ±0.1° over a range of 45 Hz to

65 Hz and ±0.2° over a range of 40 Hz to 1 kHz.

Power Supply Rejection (PSR)

PSR quantifies the ADE7761B measurement error as a percentage

of reading when the power supplies are varied. For the ac PSR

measurement, a reading at nominal supplies (5 V) is taken.

A second reading is obtained with the same input signal levels

when an ac signal (175 mV rms/100 Hz) is introduced onto the

supplies. Any error introduced by this ac signal is expressed as

a percentage of reading (see the Measurement Error definition).

For the dc PSR measurement, a reading at nominal supplies (5 V)

is taken. A second reading is obtained with the same input signal

levels when the power supplies are varied ±5%. Any error

introduced is again expressed as a percentage of reading.

ADC Offset Error

This is the dc offset associated with the analog inputs to the ADCs.

With the analog inputs connected to AGND, the ADCs still see

a dc analog input signal. The magnitude of the offset depends on

the input gain and range selection (see the Typical Performance

Characteristics section). However, when HPFs are switched on,

the offset is removed from the current channels and the power

calculation is not affected by this offset.

Gain Error

The gain error in the ADE7761B ADCs is defined as the difference

between the measured output frequency (minus the offset) and

the ideal output frequency. It is measured with a gain of 1 in

ideal frequency, which is obtained from the transfer function

(see the Transfer Function section).

Gain Error Match

The gain error match is defined as the gain error (minus the offset)

obtained when switching between a gain of 1 or 16. It is expressed

as a percentage of the output ADC code obtained under a gain of 1.