Audio program switching apparatus

• US 4,002,858 A
• Filed: 12/19/1974
• Issued: 01/11/1977
• Est. Priority Date: 12/19/1974
• Status: Expired due to Term

• Current Assignee: Edwin G. Giese
• Original Assignee: Edwin G. Giese
• Inventors: Giese, Edwin G.
• Primary Examiner(s): Cardillo, Jr., Raymond F.
• Application Number:
  US05/534,163
• Time in Patent Office: 754 Days
• Field of Search: 360/12, 360/79, 360/80, 179/100.1 C, 179/100.1 PS, 179/100.1 R
• US Class Current: 369/1
• CPC Class Codes: G11B 31/00 Arrangements for the associated working of recording or reproducing apparatus with related apparatus with cameras or projectors G03B31/00 ; recording/reproducing of music for electrophonic musical instruments G10H1/0033; automatic arrangements for answering calls or for recording messages for absent subscribers H04M1/64; telephonic communication systems adapted for combination with dictation recording and playback systems H04M11/10; connection of TV recorder with other related apparatus, e.g. TV camera or receiver, in which the TV signal is significantly involved H04N, e.g. H04N23/00, H04N5/765; combination of radio or TV with other apparatus, e.g. with vehicles H05K11/00

Abstract

A continuous primary audio program is periodically interrupted and a programmable source having a secondary program is periodically operated by an automatic electrical control in response to a control signal having a frequency outside of the audio frequency range and supplied by the secondary source. A sensing circuit selectively operates as a resonant amplifier and responds to the control signal to de-activate the secondary program and reinstate the primary program while further initiating a timing sequence by a timing circuit. Cyclic operation is provided by the timing circuit which functions to operatively attenuate the primary program and operate the secondary program after a predetermined duration of time following the control signal. Common circuitry is employed to program the secondary source by converting the resonant amplifier to an oscillator which operates with a selectively supplied source signal of a predetermined duration to provide an oscillatory output supplying the control signal to the secondary source.

Claims

1. An electrical control apparatus, comprising a transducer converting electrical audio signals to audio sound waves, a primary source connected through a connecting circuit to said transducer and supplying a primary output including a continuous primary audio program, a secondary source connected to said transducer and selectively supplying a secondary output including a secondary audio program of a predetermined time duration followed by a control signal outside of the audio frequency range, an amplifying transistor connected in common emitter configuration and having a base circuit connected to receive said secondary output and a collector circuit operatively connected to a power source, a feedback coupling said collector and base circuits and including a first feedback path having a first resistor and a first circuit portion connected to a system ground potential through a first capacitor and a second feedback path having a second capacitor and a second circuit portion connected to said ground potential through a second resistor, said amplifying transistor resonating in response to said control signal to provide a resonating output at said collector circuit, a controlled rectifier having a gating circuit operatively connected to said collector circuit and an anode circuit providing an output in response to said resonating output, a timing circuit including a selectively variable impedance operatively connected to said power source and to a timing capacitor through a junction circuit connected to said anode output circuit, said timing circuit responding to said controlled rectifier and initiating a timing sequence of a predetermined time in response to said resonating output, a first switching circuit connected to said junction circuit and providing an output connected to said connecting circuit and operatively supplying said primary program to said transducer in response to said timing sequence initiation and operatively attenuating said primary program in response to the expiration of said predetermined time, and a second switching circuit connected to said first switching output and to said secondary source and operatively supplying said secondary output to said transducer and to said amplifying transistor in response to the expiration of said predetermined time.

2. The control apparatus of claim 1, wherein said first switching circuit includes a field-effect transistor having a gate circuit connected to said junction circuit and a drain circuit operatively connected to a base circuit of a first switching transistor having an output circuit connected to said connecting circuit and selectively attenuating said primary program, said second switching circuit including a second switching transistor having a base circuit connected to said first transistor output circuit and having an output circuit connected to said secondary source.

3. The control apparatus of claim 1, and including a recording circuit connecting an originating program source to said secondary source and selectively supplying said secondary audio program for storage by said secondary source, a first switch selectively connecting said collector output circuit to said recording circuit, a second switch selectively operable and varying the impedance between said second circuit portion and said ground potential and pre-conditioning said amplifying transistor for free-running oscillation, and a third switch selectively operable between a first position connecting a storage capacitor to said power source and a second position connecting said storage capacitor to said collector circuit and operatively oscillating said amplifying transistor and selectively providing said control signal to said recording circuit for storage by said secondary source.

4. The control apparatus of claim 3, and including a transfer switch connected to said collector circuit and selectively operable between first and second transfer contacts, said third switch including a manual operator coupled to a first set of normally closed contacts connecting said first transfer contact and said storage capacitor to said power source and a second set of normally open contacts connecting said storage capacitor to said second transfer contact.