Speed measuring system

摘要

A speed measuring system with a hot wire probe arranged in a bridge circuit and with a constant temperature control circuit for the hot wire probe. The technical problem consists in providing a speed measuring system which conveys the speed of a body with respect to the ground from the speed of the air flowing around the body. The field of application of the invention is measuring the speed of sportsmen and sportswomen. Within the bridge circuit (10), a temperature compensation resistor (13) is arranged in parallel with the hot wire probe (11). In series with the temperature compensation resistor (13), the bridge circuit (10) contains a calibration resistor (14). The output signal of the constant temperature control circuit is linearised in a linearisation circuit (2). The output signal of the linearisation circuit (2) is digitised in an A/D converter (4). The binary output signals of the A/D converter (4) are forwarded via a multiplexor (5) which is controlled by interrogation signals from interrogation switches (9). The multiplexor (5) is followed by a clock- and program-controlled microprocessor (6) with storage spaces for the computing results. The interrogation signals control the retrieval from the storage spaces of the microprocessor (6), the memory values being indicated in an indicating stage (8). <IMAGE>