
22 Analog Circuits Cookbook
90 dB, the input was of course too small to see. The attenuation was
reduced to zero in 10 steps, all the steps being clearly visible on the upper
trace. The 80 to 70 dB step is somewhat compressed, probably owing to
pick-up of stray RF signals, since the device was mounted on an
experimenter's plug board and not enclosed in a screened box. With its
high gain and wide frequency response, this chip will pick up any signals
that are around.
The device proved remarkably stable and easy to use, although it must be
borne in mind that pins 8 and 9 were connected directly to the decoupled
positive supply rail, as the limite ...