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Enhanced Analog Sampling for an IBM 5100 Series 7406 System

IP.com Disclosure Number: IPCOM000051976D
Original Publication Date: 1981-Apr-01
Included in the Prior Art Database: 2005-Feb-11
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Cangelosi, MJ: AUTHOR [+2]

Abstract

A method which can obtain a digital representation of cyclic analog dat containing frequencies exceeding the resolution capabilities of the 7406 Analog Input Module has been developed. The method is similar to that used by a sampling oscilloscope, and uses the capabilities of the 7406 Digital Input Module (DIM), Digital Output Module (DOM), Analog Input Module (AIM), and Analog Output Module (AOM) to complement the simple TTL (transistor-transistor logic) circuit required for this type of sampling. An IBM 5110 or 5120 computer system using APL and appropriate microcode is used for the data acquisition and control functions.

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Enhanced Analog Sampling for an IBM 5100 Series 7406 System

A method which can obtain a digital representation of cyclic analog dat containing frequencies exceeding the resolution capabilities of the 7406 Analog Input Module has been developed. The method is similar to that used by a sampling oscilloscope, and uses the capabilities of the 7406 Digital Input Module (DIM), Digital Output Module (DOM), Analog Input Module (AIM), and Analog Output Module (AOM) to complement the simple TTL (transistor-transistor logic) circuit required for this type of sampling. An IBM 5110 or 5120 computer system using APL and appropriate microcode is used for the data acquisition and control functions.

As shown in Fig. 1, the signal to be sampled at input 7 is compared, via comparator circuit 1, to a threshold voltage (AOM) at input 9 which is slightly lower than the maximum voltage of the signal. The threshold voltage is predetermined under program control with the use of the AOM, DIM and flip-flop circuit (FF1) shown at 3. When the threshold is crossed, as shown in Fig. 2, after the 7406 AIM at input 5 becomes ready, a preloaded counter 11 counts down to zero and a pulse is emitted at a known time interval after the threshold is crossed.

The countdown starts in synchronism with the input oscillator at 13 with a relative threshold crossing start time repeatability proportional to f(osc). For this reason and its availability, the high frequency 7406 system communication module oscil...