Abstract: An FM-CW range measuring apparatus (1) to be tested generates a beat signal Fb at the frequency fb between transmitted and received waves. A simulator connected to this apparatus comprises a signal processing link, including a first HF interrupter (6), a circulator (7) and a second HF interrupter (8). A delay line (11) operating in the reflecting mode for producing the delay .tau. is connected to an input-output of the circulator means for controlling the interrupters (26, 28, 29, 33) effect opening thereof at a frequency f.sub.r (f.sub.r >2b), the first interrupter being opened during .delta. (.delta.<<1/f.sub.r), and the second interrupter during .delta.' (.delta.'.perspectiveto..delta.). The phase shift .tau.' between .delta. and .delta.' is such that the durations .delta. and .delta.' are separated from each other and that at least an echo of the order p in the delay line is defined by the equation:p.multidot..tau..perspectiveto.f/f.sub.r +.tau.'where k is a small integer.

Abstract: This indicator preferably comprises two belts; one of the belts having graduations and the other belt a mark. This mark which has been preset to one of the graduations must be moved in the same manner as the graduated belt so that the agreement is maintained. According to the invention, two controls have been provided for driving these belts the input quantities whereof are processed by an arithmetic unit, for example a microprocessor.