Abstract: A personal alarm which is compact, portable and fashionably designed. In one embodiment, this personal alarm is structurally incorporated into a wrist watch with the alarm components arranged thereon in a fanciful yet highly functional manner. This alarm may also be structurally incorporated into other conventional items such as a bracelet, pendant, necklace, keychain ornament, or any other conventional item which is often carried by the persons to be protected. In a further embodiment, the compact size is achieved without sacrificing intensity in the alarm signal by incorporating a specially wound autotransformer and an efficient switching device so as to provide a tuned warbling signal upon a piezoelectric transducer. Additionally, the alarm may be activated or deactivated by manually actuating an actuator, such as a switch or plurality of switches, in a particular sequence.

Abstract: A personal alarm which can be manually actuated to produce a high-intensity sonic alarm signal, and which is compact, portable and fashionably designed. In one embodiment, this personal alarm is structurally incorporated into a wrist watch with the alarm components arranged thereon in a fanciful yet highly functional manner. This alarm may also be structurally incorporated into other conventional items such as a bracelet, pendant, necklace, keychain ornament, or any other conventional item which is often carried by the persons to be protected. In a further embodiment, the compact size is achieved without sacrificing intensity in the alarm signal by incorporating a specially wound autotransformer and an efficient switching device so as to provide a tuned warbling signal upon a piezoelectric transducer.

Abstract: A carrier wave is frequency modulated to one of M different output frequencies that deviate from the carrier wave frequency by .+-.k.sub.1, .+-.k.sub.2 . . . .+-.k.sub.q. The carrier is modulated in response to a clocked digital signal having n data bits forming a data word, where M=2.sup.n. In response to the digital signal an n bit control signal is derived. M/2 clock frequencies synchronized with the clock data signal are simultaneously derived. An up-down counter responds to the control signal so that one bit of the control signal controls the counting direction of the counter and (n-1) of the bits control which one of the M/2 frequencies is applied to a clock input of the counter. In response to the count in the counter, orthogonal sinusoidal like waves at one of the frequencies k.sub.1, k.sub.2 . . . k.sub.q are derived. The M/2 clock frequencies are equal to k.sub.1 2.sup.P, k.sub.2 2.sup.P . . . k.sub.q 2.sup.P, where P is the number of clock frequency bits in the counter.

Abstract: A clock wave is synchronized to the frequency of serial binary data bits. Digital circuitry derives a clock wave by responding to the data bits to selectively (a) increment a reference frequency, (b) decrement the reference frequency, and (c) not change the reference frequency. The digital circuitry divides each data bit into an even number of sub-bits. The binary value associated with a first half of the divided sub-bits of a particular data bit is compared with the binary value associated with a second half of the divided sub-bits of the particular data bit. In response to the derived clock wave and the comparison, the reference frequency is derived, incremented or decremented. The frequency of the source is respectively incremented and decremented in response to first and second relations of the binary value associated with the first half relative to the binary value associated with the second half.

Abstract: Positive feedback of an acoustic signal from a loud speaker to a microphone of a loud speaker system, i.e., howling, is prevented by randomly phase shifting an electric signal containing audio information supplied to the speaker. The random phase shifting is provided by variably delaying the electric signal in a serial analog register having a shift rate determined by an output signal of a pseudo random code generator.