INFRARED ENERGY. SEE FIGURE 3 6) BALANCE OUTPUT : MAX. 15 % 〔 BO / I SA+SB I 〕 ÷ 0. 15 BO : BALANCE OUTPUT SA : SIGNAL OUTPUT ON ELEMENT A SB : SIGNAL OUTPUT ON ELEMENT B BALANCE OUTPUT IS MEASURED AT CHOPPER FREQUENCY OF 1 Hz WHEN CONNECTED TO THE AMPLIFIER OF GAIN 72. 5 dB ( AT 1 Hz ) AND SUBMITT.