Sony Corporation

Kenichi Kanazawa

Yukio Tanaka

Nobuyuki Takahashi

Bunichi Obana

An FM communication device employs a logarithmic amplifier which performs logarithmic conversion of a frequency modulated signal. The beat component level of the output signal of the logarithmic amplifier is checked with a reference level for detecting interference. With the construction set forth above, the FM communication device, according to the invention, detects the ripple of the received FM signal caused by interference of another FM signal by means of the logarithmic amplifier which converts the received FM signal logarithmically and the detection circuit which AM-detects the output signal of the logarithmic amplifier, so that the interference can be detected via the output signal of the detection circuit. In the preferred construction set forth above, the logarithmic amplifier which is often utilized in a detection system for reception magnitude is sufficient as an amplifier circuit required for detecting the interference, and no high-gain and high-performance amplifier is required.

FM communication device with avoidance of interference by substantially

A control circuit uses an adjustable resistance to generate a first control signal whose amplitude varies with the setting of the resistance and a second, step-like control signal whose level changes from a first to a second level at a predetermined setting of the resistance. The variable resistance is coupled to the collector of one of a pair of transistors whose emitters are commonly connected to a reference potential. The adjustable resistance's tap, which provides the first control signal, is connected to the base of the one transistor. A collector impedance and the variable resistance are coupled between the collector circuit of the one transistor and a voltage source. An output of the impedance is connected to the base of the other transistor, whose collector provides the second control signal. As the setting of the adjustable tap increases, the first control signal and the voltage at the base of the one transistor correspondingly increase from a first toward a second amplitude until the predetermined setting is reached. Then the relative conductivities of the transistors are reversed, and the first control signal reverts to its first amplitude, while the second control signal undergoes a step-like transition. Additional increases in the setting of the adjustable resistance again raise the first control signal from its first amplitude.

Control circuit for generating a step-type control signal and a

A controllable rectifier circuit which may be used in a power supply selectively produces a half-wave or a full-wave rectified signal. The rectifier circuit includes a pair of input terminals for receiving an AC signal and a bridge rectifier coupled to the input terminals and including a pair of output terminals across which a rectified AC signal is produced. The bridge rectifier comprises a first current path including a switchable rectifier for conducting positive half cycles of the AC signal and a second current path including a switchable rectifier for conducting negative half cycles of the AC signal. A pulse generator is supplied with reduced amplitude versions of the positive and negative half cycles of the AC signal, in sequence, to produce an output pulse when the reduced amplitude of the half cycle supplied thereto is less than a predetermined level. A non-reduced half cycle of the AC signal is selectively supplied to the pulse generator to prevent the pulse generator from generating an output pulse during that half cycle so that an output pulse is generated only during the beginning and ending portions of the other half cycle. The generated output pulses are supplied to each of the switchable rectifiers, whereby the bridge rectifier rectifies both half cycles of the AC signal when the non-reduced half cycle is not supplied to the pulse generator, and the bridge rectifier rectifies only the other half cycle of the AC signal when the non-reduced half cycle is supplied to the pulse generator.

Growing community of inventors

Atsugi, Japan

Kenichi Kanazawa