Bradley 156 Oscilloscope Calibrator

This calibrator provides signals for calibration of the vertical and horizontal deflection coefficients of oscilloscopes.

For the vertical deflection coefficients, a DC or square wave signal can be selected. The horizontal (timebase) ranges are calibrated using pulse trains that are derived from a crystal oscillator using a sequence of dividers.

Both of these facilities feature a "deviation" control intended to align the displayed signal with the oscilloscope graticule lines; the error can then be deduced from the meter reading.

There is also a "fast rise" output that provides a pulse with about a 3 ns risetime for checking oscilloscope risetime.

The 156 was superseded by the Model 192, which was lighter, featured extended ranges and provided a 1 ns pulse risetime output.