Browse Prior Art Database

Digital Phase Encoded Detection System

IP.com Disclosure Number: IPCOM000091967D
Original Publication Date: 1968-Jul-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 50K

Publishing Venue

IBM

Related People

Bailey, DL: AUTHOR

Abstract

Long wavelengths in sensed data from a phase-encoded source are detected to prevent misinterpretation of the received data. Such detection is by forcing the appearance of all 1's or all 0's between occurrences of such long wavelengths by logically setting latch type circuits. Increased reliability is realized through long wavelength detection since the signal-to-noise ratio is more favorable. This circuitry operates in conjunction with an analog derived clock ADC, such as shown in U. S. Patent 3,293,555 and in an article by in the IBM Technical Disclosure Bulletin, August 1964, pages 205 - 207.

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Digital Phase Encoded Detection System

Long wavelengths in sensed data from a phase-encoded source are detected to prevent misinterpretation of the received data. Such detection is by forcing the appearance of all 1's or all 0's between occurrences of such long wavelengths by logically setting latch type circuits. Increased reliability is realized through long wavelength detection since the signal-to-noise ratio is more favorable. This circuitry operates in conjunction with an analog derived clock ADC, such as shown in U. S. Patent 3,293,555 and in an article by in the IBM Technical Disclosure Bulletin, August 1964, pages 205 - 207.

The following components of the circuitry shown in the drawing compare directly with components in the aforementioned patent and article. These are frequency divider 7, input line 10, voltage controlled multivibrator VCM 14, line trigger 18 including the associated logic and capacitors present in the article and patent, and operational amplifier 28. The latter includes the functions of mixer 28, filter 30, and frequency control 32 of both the patent and the article. Like reference numerals are used for these components and, since the operation of these components is substantially the same as in the patent and article, a description of the operation of these components is omitted here. The specific circuitry contained in block 25 is shown in Figure 5 of patent 3,293,555, including And's 40 and 45. The circuitry shown here utilizes the outputs of 40 and 45 for additional purposes as is pointed out.

Sensed data introduced at terminal 10, as shown in the time base drawing, contains 1's as are indicated by negative transitions at the end of the pulses, while 0's are indicated by a rise at the beginning of a pulse, the transition between 1's and 0's being designated by intervening long wavelengths as shown. A downlevel at 10 concurrent with the downlevel of trigger 18 on line 12 and the presence of an 11 pulse conditions And 40 to produce signals 15 to reset latch
24. This sequence occurs for every negative long wavelength, i.e., a 1 to 0 transition. Conversely, the presence of pulses concurrently on 10, 11, and 12 causes And 45 to produce output 16 to set latch 24. Thi...