Browse Prior Art Database

Adaptive Detector

IP.com Disclosure Number: IPCOM000090983D
Original Publication Date: 1969-Sep-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 4 page(s) / 40K

Publishing Venue

IBM

Related People

Mortlemans, JM: AUTHOR

Abstract

The adaptive detector is a decoder of double-frequency encoded information which allows wide variation of the data rate of the incoming signals. The circuit is relatively frequency insensitive by making it adaptive to the incoming signals and the relaxation times of the two single-shots generating the window waveform in the basic data separation circuit. For lower and middle frequency operation, an integrator and a voltage feedback control are provided for each single-shot. For higher frequency operation, the recuperation characteristic of the single-shot is used to control the relaxation time. Basic Data Separation Circuit

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 39% of the total text.

Page 1 of 4

Adaptive Detector

The adaptive detector is a decoder of double-frequency encoded information which allows wide variation of the data rate of the incoming signals. The circuit is relatively frequency insensitive by making it adaptive to the incoming signals and the relaxation times of the two single-shots generating the window waveform in the basic data separation circuit. For lower and middle frequency operation, an integrator and a voltage feedback control are provided for each single-shot. For higher frequency operation, the recuperation characteristic of the single-shot is used to control the relaxation time. Basic Data Separation Circuit

With integrator outputs 12 and 17 shorted to ground and voltage supplies 13 and 18 held constant at 6 volts, the a basic data separation circuit is realized. The unseparated data appears on line 1 at the input to inverter 2 in the form shown as signal 1. The output of inverter 2 is fed to And 7 through single-shot SS 3 and also through inverter 4 and single-shot SS 5. SS's 3 and 5 generate a ten microsecond negative pulse each time their input signal is a negative transient. The ten microsecond pulses are termed spikes. And 7, also And's 9 and 20, produce a negative output when both inputs are positive, otherwise the output is positive. The resulting signal 8 shown as appearing at line 8 gives a positive ten microsecond pulse for each transition of the unseparated data.

Single-shot SS 15 generates a window waveform which is used to open gate 20 in order to detect a transition between two clock pulses. Delay single-shot SS 10 produces a pulse at line 11 which defines the delay of the window at 16 with respect to the preceding clock pulse. The duration of the window corresponds to the relaxation time of SS 15 and is equal to one half of clock time. The window waveform, therefore, is a symmetrical square wave. The delay is equal to the relaxation time of SS 10 which is normally taken as one-sixth of clock time. The output of SS 15 is fed back through And 9 in order to prevent data pulses from passing to SS 10. The signals appearing on lines 11 and 16 are shown as signals 11a and 16 respectively. The output of And 7, appearing on line 8 as a positive-going spike for each data and clock pulse, and the output of SS 15, after inversion by inverter 19, are fed into And 20. The output of And 20 is shown as signal 21 appearing on line 21 as a negative-going spike for each data pulse.

With resistor R44 at 6 volts and line 42 at 3 volts and with a positive level at the input to SS 10 on line 40, diode D41 does not conduct. Current flows through R44 into the base of transistor T48, causing the latter to be forward biased. This shorts out line 50 to ground through T48. With the base of transistor T52 at ground, T52 does not conduct and the output on line 54 assumes the voltage V of 3 volts on line 42. In this condition, the voltage on line 46 is at +3 volts while voltage on line 47 is .7 volts, the base vol...