LTZ1000 Noise Measurement

The LTZ1000 voltage reference noise is measured in the 0.1Hz -10 Hz band according to the data published on the datasheet.
The voltage to be measured is applied to an input of a low noise differential amplifier with a gain of 100; at the other input is applied a voltage obtained from a NiMH battery (known for low noise). After a high-pass filter, the signal is amplified 1000 times and then passed through a low-pass filter with a cutoff at 10 Hz.
The amplitude of the noise is then measured with an oscilloscope.
The accuracy of the response curve is tested with a low-frequency spectrum analyser; an example is visible in the picture below.