TELEMETERING SYSTEM FOR MULTI-CHANNEL DATA OVER VOICE GRADE TELEPHONE LINES

• US 3,786,190 A
• Filed: 12/23/1971
• Issued: 01/15/1974
• Est. Priority Date: 12/23/1971
• Status: Expired due to Term

• Current Assignee: John R. Pori
• Original Assignee: John R. Pori
• Inventors: Pori, John R.
• Primary Examiner(s): Claffy, Kathleen H.
• Assistant Examiner(s): D'Amico, Thomas
• Application Number:
  US05/211,221
• Time in Patent Office: 754 Days
• Field of Search: 179/2DP,2R,15FD 178/66R 340/170,171R,27R,182,184 332/16R,16T,29M,29R,21,28 329/110,112,140 325/30,47,145,344,349
• US Class Current: 370/482
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: H04M 11/002 with telemetering systems telemetering in general G08C
• CPC Class Codes: Y10S 128/904 Telephone telemetry

Abstract

A telemetering system for multi-channel data such as EEG data where eight channels of such data are frequency modulated by eight different carrier frequencies and transmitted over a telephone line pair and then filtered and demodulated. The demodulator for each channel includes only a single inductor which is matched with the modulator inductor.

Claims

1. A telemetering system for multi-channel data where the transmission medium is a single voice quality communications channel said system comprising:

frequency modulation means for receiving said multi-channel data such means including in each channel a single inductor coupled with capacitor means forming a resonant circuit and tuned for providing a unique carrier frequency for each data channel said modulation means being frequency modulated by said data and also including a transistor for each channel with said resonant circuit being connected across its emitter and collector and tuned to a carrier frequency, such circuit including fixed d.c. biasing means for said base and including said single inductor which responds to a change of d.c. current through it to change its inductance value, said base of said transistor being responsive to data from a channel and being direct coupled to said channel to change said d.c. current in accordance with the signal magnitude of said data whereby said carrier frequency is frequency modulated by said data, means for coupling said frequency modulation means to said communications channel, phase detector means adapted for being coupled to said communications channel for demodulating said signal transmitted by said channel said phase detector means including a plurality of circuits resonant at each of said carrier frequencies each resonant circuit having an inductor identical with respect to electrical characteristics to said inductor in the corresponding cannel of said frequency modulation means.