The paper discusses the properties of display systems using frequency rather than time coding of the individual image elements. Various coding techniques, all making use of a dispersive delay line, are compared by means of time-frequency diagrams showing the nature of the coding operation. A detailed analysis is given of one such technique used in conjunction with an acoustic light diffraction cell as the display device. Experimental results for this system are presented in the form of measured modulation transfer functions and photographs of standard television test patterns displayed with this technique.