Abstract: An amplification circuit comprising a device for compensating for its input current. The amplification circuit includes an amplifier and a capacitor located on the input side of the amplifier. The input-current compensation device consists of a current generator, generating a current Ig, a switch and a device for measuring the average current charging or discharging the capacitor during the time that the switch is open. The current Ig is such that: Average current=Ia-Ig, where Ia is the input current of the amplifier. The value of the average current is close to zero. The value of the current Ig which the current generator must output, so as to make the average current close to zero, is calculated using the device for measuring the average current. The invention particularly applies to a circuit for restoring the DC component of a video signal.

Abstract: Frequency modulated signals are demodulated through a limiter circuit that chops the signal to give pulses whose occurrence frequency is proportional to the instant frequency of the received signal. The invention is devoted to a new processing of those pulses. The leading edges of the pulses are time integrated. The obtained signal is then as usual, low pass filtered to give the demodulated signal. The main advantage of this new processing is that the circuit that makes this processing does not implement delay lines and can then be made as a single chips.

Abstract: In a detector for detecting a frequency-modulated light wave including a PIN photodiode (2), biasing means (11, 12, 15) are introduced which are capable of automatically forward biasing or reverse biasing the PIN photodiode (2) depending on the received light power. The output voltage of a transimpedance preamplifier stage (6) receiving the signal from the PIN photodiode (2) is thus automatically limited to a value below the saturation threshold of this transimpedance preamplifier stage (6).

Abstract: The invention concerns a thrust plate spring for a disc brake with a caliper (10) sliding on a fixed support (12) comprising a first friction component (14) which is capable of being applied to one surface of a brake disc by means of a brake actuator through a thrust plate (34), and a second friction component which is capable of being applied to the other surface of the disc through the sliding caliper. According to the invention, the spring (64) comprises an elongated metal leaf which is fixed to the thrust plate (34) and which co-operates with an external peripheral portion (80) of the caliper (10) pushing the plate (34) radially outwards by bearing radially against the corresponding surfaces (50) associated with the fixed support (12).

Abstract: The protection device for a laser diode supplied by the superimposition of a DC biasing current and a variable information-carrying current, through an opto-electronic feedback system, comprises a variable resistor connected upstream of the laser diode and of the feedback system so as to form a closed loop with the information-carrying current source and so as to ensure that the laser diode is biased before any injection of information-carrying current into this diode.

Abstract: A frequency demodulation device having a circuit for limiting the amplitude of a frequency modulated signal, an integration circuit and a low pass filter. Two successive output signals from the amplitude limiting circuits are integrated in the integrating circuit in accordance with first and second predetermined time constants.The signal is then fed to the filter which extracts the mean value from the output signal of the integrating circuit. This mean value is proportional to the modulated wave frequency and thus determines that frequency.

Abstract: A drum brake includes a pair of brake shoes which are carried by and pivotally anchored to a backing plate. The pair of shoes are engageable with a brake drum to effect a brake application. A running clearance is maintained between the brake shoes and the drum when the brakes are released by an adjusting member which includes an adjusting lever pivotally carried by one of the shoes and a fixed-length spacer carried between the adjusting lever and the other brake shoe. An extensible member is carried between one end of the adjusting lever and the one brake shoe and a three-bar linkage effects an extension of the member to compensate for wear of the brake shoes. The adjusting lever forms one bar of the linkage and carries the other two bars. The second bar of the linkage is pivotally engaged with the adjusting lever and with the spacer and is biased so as to move the spacer away from the adjusting lever during a brake application.