U SOO54l0735A United States Patent [19] [11] Patent Number: 5,410,735 Borchardt et al. - [45] Date of Patent: Apr. 25, 1995 [54] WIRELESS SIGNAL TRANSMISSION 4,739,413 4/1983 Meyer - SYSTEMS, METHODS AND APPARATUS 4,771,344 9/1988 Fallacaro e141- - 4,847,903 7/1989 Schotz ................................... .. 381/3 [76] Inventors: Robert L. Borchardt, 120 E. End '. ' . ' ' Ave" New York, NY. 10028; _(L1st contlnued on next page.) _ William T. McGreevy, 43 Thompson FOREIGN PATENT DOCUMENTS Ave., Babylon, NY. 11702; Ashok _ Naw ge’ 3L7‘) 34th St.’ Apt.#3F, 0040481 2/1988 Japan .............................. .. 358/194.l Astoria, NY. 11105; Efrain L. OTHER PUBLICATIONS §°d"lf1“ez’§6; Y" “New 902-928 MHZ Band Now Open!”, Spec-Com mo yn’ ' ' Journal, Sep/Oct. 1985, cover page and p. 9. __ [21] Appl. No.: 259,339 Federal Register, vol. 50, Aug. 22, 1985, Final Rulemak . ing re addition of 902-928 MHz band to Amateur Radio [22] E169 J‘m' 13,1994 Service Rules, pp. 33937 through 33940. Related Us. Application Data (List continued on next page.) . - _ Primary Examiner—Reinhard J. Eisenzopf [63] ggéietanuation of Ser. No. 822,598, Jan. 17, 1992, aban Assistant Examiner_Andrew Faile [51] In G 6 H04B 1/00 Attorney, Agent, or Firm-Levisohn, Lerner & Berger t. > ............................................. .. [52] US. Cl. .................................... .. 455/42; 455/110; [571 ABSTRACT 455/205; 455/ 344; 455/ 351 ; 381/3 Systems, methods and apparatus are provided for con [58] Field of Search .................................. .. 455/42-43, ‘ducting local wireless audio signal transmissions from a 455/66, 95, 110-113, 120-125, 205, 208, 214, 'local audio signal source to a person within a local 344, 351, 352, 127, 343; 348/725, 731, 738; signal transmission area. In certain embodiments, the 381/ 2—3; 379/62; 331/64, 96 transmissions are conducted over the 900 MHz local [56] References Cited transmission band to a portable receiver unit supported on the headband of a stereo headphone unit. The re U'S' PATENT DOCUMENTS ceiver unit serves to down convert the 900 MHz signal 2,287,065 6/1942 Roberts . to a local frequency band which is received by an FM £01121 Ct 81- - receiver of the receiver unit which serves to reproduce 9 9 31' er . - - . _ 3,590,382 6/1971 Kenney ............................. .. 455/110 the who slgn a1? therefrom Whlch are’ 1“. tum’ con 3 697 941 10/1972 Christ verted to acoustlc slgnals by electroacoustw transduc 3Z934Z201 1/1976 Majefslti .............................. .. 381/14 ers of the headphmle- A transmitter unit includes a 3,984,625 10/1976 Camras . ceramic resonator stabilized FM transmitter, as well a 4,021,737 5/1977 Trask ................................. .. 358/189 ?lter for suppressing high frequency noise in an audio 4,097,893 6/1978 caqlras - modulation signal, a stereo audio multiplexing unit uti gveléltragb et a1- ' lizing a 3f]; subcarrier and an overmodulation detection 4’386’436 3/1983 Kills: ett unit. In certain embodiments, the receiver unit is pow 4:392:022 7/1983 Carlson _ ' ‘ ered by a rechargeable battery which is recharged from 4,434,510 '2/1984 Lemelson . the transmitter unit. 4,484,156 11/1984 Khanna ............................... .. 331/96 4,549,179 10/1985 Ste'ndardo . 4,621,374 11/1986 Micic et a1. 4,685,133 8/1987 Iggulden . 4,694,338 9/ 1987 Tsinberg . 29 Claims, 12 Drawing Sheets my I 212 1 214 f 218 1 218 lnrltill'lll;ED E 1111111111 _ ‘"15" 05111111011 _\220 230 mimic 2“ T (24o (244 250 24 H4 mum: maven umvsn (226 242 252 5,410,735 Page 2 U.S.‘PATENT DOCUMENTS __ 1-18 and 35-10 through 35-15. 4,916,532 4/ 1990 Streck et a1. “TVC-9 GaAs FET 33 cm ATV Downconverter”, 4,939,770 7/1990 Makino ............................... .. 379/61 Spec-Com Journal, Sep./Oct. 1986, cover page and pp. 4,980,665 12/1990 Schotz . 20-21. 4,984,296 1/1991 Schotz . Jerry Iggulden, Rule Making Petition to Federal Com 5,012,350 4/1991 Streck et a1. ........................ .. 358/86 munications Commission, Sep. 11, 1985. 5,023,933 6/1991 Karkota, Jr. .................. .. 455/307 5,151,668 9/1992 Kim ....................... .. 455/110 FCC Public Notice Report No. 1544, Oct. 21, 1985 (two 5,299,264 3/1994 Schotz et a1. ......................... .. 381/2 pages) and certi?cation that the same is a true and cor rect copy. OTHER PUBLICATIONS Hap Grif?n, “HAM-TV, Amateur Radio’s Visual Fenton, Radio Electronics, Nov. 1987, p. 4. Mode That Blends, Voice, Video, Photography & Ex “Cordless TV Headphones” SYNC catalog, Spring perimentationl”, A5 Amateur Television Magazine, Sep. 1989, p. 5. 1984, pp. 6-9. “Wireless TV Marriage Saver” DAK catalog Summer P. C. Electronics, Advertisement, A5 Amateur Televi 1989, p. 1. sion Magazine, Sep. 1984, cover/table of contents page Electronic Circuits; Collins Raymond; 1980; p. 289 (?g and pp. 20-23. ure 21-50). Henry B. Ruh, “All About Amateur TV”, QST Maga “A Complete Single Chip AM/FM Radio Integrated zine, Jun. 1981, pp. 11-12. Circuit” Okanobu et a1., IEEE vol. CE-28, No. 3, E. Laird Campbell, “Amateur TV-The Easy Way”, Qst Aug./ 1982; pp. 393-407. -Magazine, Nov. 1962, pp. 33-41 and 150. “Reference Data for Engineers: Radio, Electronics, _ 198] Radio Amateur’s Handbook, published by the Computer and Communications”, Howard W. Sams & American Radio Relay League, cover page and pp. Co., Inc., 7th Edition, 1986, cover page, and pp. 1-5, 14-28 to 14-33. US. Patent Apr. 25, 1995 ~ Sheet 1 of 12 5,410,735 210 26 30 L24 28 38 FIG./ 37 US. Patent Apr. 25, 1995 Sheet 2 of 12 5,410,735 212 . 5% Na952:5:2a 05% 55s: as. 255s:5225.fl 8s23$a5mm AI11»;2552255i:32a5 in21a :22;5::‘Nwt g. k\A\\\sa 55:52.55s_ \2:522? ‘i:,2.a_IJ M:2 “EEG z US. Patent Apr. 25, 1995 - Sheet 3 of 12 5,410,735 \_—'304/ LPF 3l0 F / 6'; 25 "~92 F ————— —'- —- “1/ 90 I"? {no I ‘ l * ‘ ___1h‘%%%J€L¥8€E A i "3 I 0mm _____ __1?° I l | I 102 i ‘ ~94 if W(I26 4/ 0 To , I "a | i - m : HEADPHONE ' "6 ' I RECHARGING : 1 4 ma 1 INPUT I l l _I- | 1 F "7 I L __________ __J l =- l ' r l L ________ __J US. Patent Apr. 25, 1995 Sheet 4 of 12 5,410,735 3; 4/l2 E: 52%V 2 52.3 58:: 'r-______lullli'llllllull -___.__.. N2 22 _U.S. Patent Apr. 25, 1995 Sheet 5 of 12 5,410,735 F/6‘.5 OFF- US. Patent Apr. 25, 1995 Sheet 8 of 12 5,410,735 is_ _. .N: _ a?mE_ ~ "28%§ noz:.22k-52 n3>_g oN \3:E 5%.J70/?..1I $6_ |.\.W\|FilllI aw?a“W_o: l1I1olLilF1I as; 5ca__ ..m\."\MN EN.I 2$§ @222 o2 2%5:: 3a2N £835: =2; US. Patent Apr. 25, 1995 Sheet 10 of 12 5,410,735 624 %non 220%6'6 vcc l2v 604 flab>620 / I-SV 600/ V00 U.S.'Patent Apr. 25, 1995 Sheet 12 of 12 5,410,735 F/6.8 5,410,735 1 2 horizontal frequency of the video signal (approximately WIRELESS SIGNAL TRANSMISSION SYSTEMS, 15.734 kilohertz in, an NTSC signal) and harmonics METHODS AND APPARATUS thereof. Applicants have found that the use of a 38 kilohertz subcarrier to form the multiplexed stereo sig This application is a continuation of application Ser. nal causes mixing with the second harmonic of the No. 07/822,598, ?led Jan. 17, 1992, now abandoned. NTSC signal, resulting in audible beat interference. In BACKGROUND OF INVENTION an attempt to overcome this problem, applicants have The present invention relates to wireless signal trans instead employed a subcarrier having a frequency equal mission systems, methods and apparatus, for example, 10 to two times the horizonal frequency of the video sig radio transmission apparatus for transmitting audio sig nal, approximately 31.5 kilohertz. However, similar nals within a local transmission area to a portable radio beat interference problems resulted. Applicants further receiver means carried on the person of the user. attempted to overcome this problem with the use of a Personal wireless audio signal transmission apparatus subcarrier equal to four times the horizontal video fre include systems which transmit audio signals, such as quency, but were unsuccessful due to a loss of stereo television audio signals, by means of infrared light re separation resulting from the use of an excessively high ceived by a personal infrared light receiving device subcarrier frequency. worn by a listener. It will be appreciated that such With the introduction of digital audio recording me transmission systems require a line-of-sight transmission dia, such as compact discs, and digital reproduction path, so that the system is not workable if walls, furni 20 techniques, the ability to reproduce high quality audio ture or other objects intervene between the transmitter and receiver. Accordingly, while infrared transmission signals having superior frequency response and wide systems may be useful where, for example, a person is dynamic range requires the provision of a similarly seated several feet from a television receiver to which capable personal wireless transmission system. The the infrared transmitter is connected for transmitting 25 transmitter of such a system must be capable of modu television sound, the transmission path may be inter lating a carrier without introducing audible distortion at rupted if, for example, the listener turns his or her head the receiver, for example, due to overmodulation.