1. Low boost system
2. Low boost
The signals applied to each input are mixed and passed through a two stage low pass filter. Since the signal level is
reduced by the low pass filters it is amplified between the two low pass filter stages to correct the level. The signal
that has passed through the second low pass filter is reversed in phase with respect to the input signal and is input to
each power amplifier.
3. Channel 1 and 2 amplifiers
The positive phase input signals are input to the normal (+) inputs, and the reverse phase signal that was passed
through the low pass filter is input to the inverting (–) inputs.
4. Common amplifier
The signal that was passed through the low pass filter is phase inverted by an inverting amplifier and input to the
common amplifier's inverting (–) input. Note that this input signal is reverse phase from the signal input to the
channel 1 and channel 2 amplifier inverting (–) inputs. Since the amplifier's plus input is connected to Vref, it
functions as an inverting amplifier.
This circuit achieves a large dynamic range since the common amplifier and the channel 1 and channel 2 amplifiers
operate in reverse phases.