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EP0599522A1
Expired / Lapsed
EP
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Optical transceiver with improved range and data communication rate
Assignee: HP Inc
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Filing: 1993-11-12
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Granted: —
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Expires: 2013-11-12
Abstract
Abstract An IR transceiver (10) for use in low-power, low cost environments such as portable computers and hand-held calculators. The transceiver can transmit data at higher, selectable baud rates and at greater distances than previously possible. On the transmitting side the transceiver elements include a serial interface device (12), encoder circuitry (14) and an IR transmitter (16) with LEDS (34) having fast turn-on and turn-off times. On the receiving side are decoder circuitry (20) coupled to the serial interface device (12) and an IR receiver (18) designed specifically for a photo diode (D1). A baud rate generator provided by the serial interface device (12) sets the baud rate in the encoding and decoding circuitry (14, 20). The receiver portion of the IR transceiver (10) automatically sets itself to the baud rate of received data. Because of the baud rate selectability, the IR transceiver (10) is compatible with prior IR transceivers that are limited to fixed baud rates.
Inventors
- 👤 Kevin W. Bartig
- 👤 Richard D. Crawford
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 07:22
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/11; H04B10/114; H04B10/1143; H03; H03F; H03F3/00; H03F3/04; H03F3/08; H04B10/40
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
69 words
An optical communication device for receiving serial communication at various selectable baud rates, comprising: a photo diode (D1) for receiving light pulses and converting the light pulses into electrical pulses; an amplifier (Q1) for amplifying the electrical pulses; a high pass filter (R3, C2, Q2) for filtering out lower frequency amplified electrical pulses; and a converter (36) for converting the filtered pulses into pulses having predetermined digital signal levels.
Claim 2
Dependent Claim
33 words
The optical communication device of claim 1 wherein the converter (36) comprises a comparator (36) for comparing the electrical pulses with a reference value to transform the pulses into predetermined digital signal levels.
Claim 3
Dependent Claim
14 words
The optical communication device of claim 1 wherein the reference value is ground voltage.
Claim 4
Dependent Claim
40 words
The optical communication device of claim 1 wherein the high pass filter (R3, C2, Q2) comprises a feedback circuit for feeding the lower frequency pulses back to the photo diode (D1) to divert such pulses away from the amplifier (Q1).
Claim 5
Dependent Claim
34 words
The optical communication device of claim 1 wherein the amplifier (Q1) comprises a first transistor (Q1) having its base coupled to the photo diode (D1) and its collector AC coupled to the converter (36).
Claim 6
Dependent Claim
137 words
The optical communication device of claim 4 wherein the high pass filter comprises: a second transistor (Q2) having its collector coupled to the base of the first transistor (Q1) and the photo diode (D1), and having its base coupled to the collector of the first transistor (Q1); and a capacitor (C2) coupled at one end to the emitter of the first transistor (Q1) and the base of the second transistor (Q2) and coupled at the other end to ground, the first and second transistors (Q1, Q2) forming a feedback path for feeding lower frequency pulses back toward the photo diode (D1) to divert such pulses away from the base of the first transistor (Q1) and into the collector of the second transistor (Q2), and the capacitor (C2) for filtering higher frequency pulses out of the feedback path.
Claim 7
Dependent Claim
196 words
An optical communication transceiver for receiving and sending serial communication at various selectable baud rates, comprising: (a) a serial interface device (12) for transmitting and receiving a serial bit stream at a selectable baud rate, the baud rate determined by a selectable rate of a clock signal; (b) an encoder (14) for encoding the serial bit stream into electrical pulses, the encoder comprising: a counter (24) responsive to the serial bit stream and a clock signal for counting at the selected clock rate; and logic circuitry (26, 28, 30) coupled to the counter for creating an electrical pulse for a predetermined number of clock signals in each count; (c) an optical transmitter (16) coupled to the encoder for transforming the electrical pulses into light pulses; (d) an optical receiver (18) for receiving light pulses and transforming them into electrical pulses; and (e) a decoder (20) for decoding the electrical pulses into a serial bit stream, the decoder including a counter (38) responsive to setting of a flip flop (40) for counting at the selected clock rate toward a predetermined count corresponding to a full bit time, thereby transforming the electrical pulses into a serial bit stream.
Claim 8
Dependent Claim
19 words
The optical communication device of claim 7 wherein the clock signal is generated by the serial interface device (12).
Claim 9
Independent Claim
75 words
A method of communicating information optically, comprising: selecting a baud rate; generating a serial bit stream at the selected baud rate, each bit occupying its full bit time; encoding the serial bit stream into electrical pulses, each pulse occupying a fraction of the serial bit time, by sensing output of a counter (24) counting at a multiple of the selected baud rate; and driving an LED (34) with the electrical pulses to generate light pulses.
Claim 10
Dependent Claim
55 words
The method of claim 9 including: receiving a series of light pulses with a photo diode (D1) and transforming them into electrical pulses; and decoding the electrical pulses into a serial bit stream by enabling a counter (38) in response to an electrical pulse, the counter counting at the multiple of the selected baud rate.
References Cited (Backward Citations)
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