TF 2370 is a spectrum analyser /'tracking signal generator/counter covering the range 30 Hz to 110 MHz in sweep widths varying from 200 Hz to 100 MHz and with resolutions varying from 50 kHz to 5 Hz. The user selects input sensitivity, sweep width, centre frequency and filter resolution and a wired logic programme selects best r.f./i.f. gain ratio, sweep rate and filter bandwidth. One of the disadvantages of high resolution swept-filter type spectrum analysers is the long sweep times necessary to scan the required frequency band. In TF 2370 the longest sweep time is 100 seconds. To enable the data scanned during this time to be clearly presented and subsequently analysed, a digital store, consisting of a 256 x 512bit m.o.s. f.e.t. dynamic shift register, records the processed signal from the wide range logarithmic amplifierand displays this stored data at a flicker free 70 Hz rate on a bright 12 x 10 cm camera monitor cathode ray tube. Superimposed on this display is an electronic graticule which may be moved in both vertical and horizontal directions to facilitate accurate measurements. The stored display of a single shot scan can be measured in frequency to counter accuracy by positioning an electronic cursor in the desired position. Additionally the electronic cursor can be used to manually edit or update the stored image or can be used as a meter, thus providing the facilities of a selective level test set.