SE328795B - - Google Patents

Abstract

1,061,803. Locating an obstacle. H. AUBERT and J. SOKOLOWSKY. June 29, 1964 [July 5, 1963; Dec.24, 1963], No.26749/64. Heading G1N. In an apparatus for generating audible sounds which are variable according to the distance of a vehicle from an obstacle and constitute a measure of the distance, wherein the sounds are obtained from the beat of two signal generating units, one of a fixed frequency and the other of a frequency varying according to the distance to the obstacle of electric conductors located on the vehicle, a number of paths including different sound modifying means are provided between the beat detector and an electro-acoustic transducer and their selection is controlled by the beat frequency to produce sounds having different characteristics. The beat signal is applied to modulate an auxiliary oscillator the frequency of which may be 800- 1000 c/s and the different characteristics applied to the transducer may be the resultant modulation or the beat frequency itself according to their respective frequencies, filters in the respective paths passing or blocking the signals. Transistor oscillating gating, and amplifying circuitry is described with reference to Fig. 1 (not shown). The main oscillators are synchronized to give no beat at an extreme limiting distance, and as the vehicle closes to less than the limiting distance from the obstacle, the beat is developed, and serves to key the auxiliary oscillator, the rhythm increasing as the distance diminishes until the fundamental frequency itself takes over the audible informant role. A single electrode may be used, and suitable perforated metal electrodes are described with reference to Fig. 2 (not shown). Boxing arrangements for the cab apparatus are described. In alternative arrangements referred to, the auxiliary oscillator is replaced by a multivibrator, a frequency changer is coupled to the variable oscillator, or a radio electric link is provided between the sensor and the variable oscillator.