Editing ParaNet BBS/All About Gravitational Waves (section)

==The simplest detector==

Monopole gravity waves generate small impulse currents that may
be coupled to an op-amp configured as a current-to-voltage converter, as
shown in Fig. 2.  The current-to-voltage converter is a nearly lossless
current-measuring device.  It gives an output voltage that is
proportional to the product of the input current (which can be in the
picoampere range) and resistor R1.  Linearity is assured because the
non-DC-connected capacitor maintains the op-amp's input terminals at
virtual ground.

The detector's output may be coupled to a high-impedance digital
or analog voltmeter, an audio amplifier, or an oscilloscope.  In
addition, a chart recorder could be used to record the DC output over a
period of time, thus providing a record of long-term "shadow-drift"
effects.  Resistor R2 and capacitor C2 protect the output of the
circuit; their values will depend on what you're driving.  To
experiment, try a 1k resistor and a 0.1 uF capacitor.

The output of the detector (Eo) may appear in two forms,
depending on whether or not stabilizing capacitor Cx is connected.  When
it is, the output will be highly amplified 1/f noise signals, as shown
in Fig. 3-a.  Without Cx, the circuit becomes a "ringing" circuit with a
slowly-decaying output that has a resonant frequency of 500-600 Hz for
the component values shown.  In that configuration, the circuit is a
Quantum Non-Demolition (QND) circuit, as astrophysicists call it; it
will now actually display the amplitude variations (waveshapes) of the
passing gravitational-impulse bursts, as shown in Fig. 3-b.

An interesting variation on the detector may be built by
increasing the value of sensing capacitor C1 to about 1000-1600 uF.
After circuit stability is achieved, the circuit will respond to almost
all gravity-wave signals in the universe.  By listening carefully to the
audio output of the detector you can hear not only normal 1/f noise, but
also many "musical" sounds of space, as well as other effects that will
not be disclosed here.