Browse Prior Art Database

Signal Processing Subsystem

IP.com Disclosure Number: IPCOM000061788D
Original Publication Date: 1986-Sep-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 3 page(s) / 33K

Publishing Venue

IBM

Related People

West, LP: AUTHOR

Abstract

A flexible processing adapter for multiple application is described. The adapter subsystem for the IBM Personal Computer (PC) is provided with a combination of new features. This particular arrangement provides significant advantages in complexity of functions performed and in functional flexibility. These features, in combination, provide capabilities to provide functions not available in other, generally comparable designs. Fig. 1 shows salient details of the adapter design. One key element of the subsystem is that it provides a programmable signal processor (PSP) in combination with read/write RAM (random-access memory). Use of RAM permits the PC to change the nature of the adapter by loading different programs into the PSP RAM.

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Signal Processing Subsystem

A flexible processing adapter for multiple application is described. The adapter subsystem for the IBM Personal Computer (PC) is provided with a combination of new features. This particular arrangement provides significant advantages in complexity of functions performed and in functional flexibility. These features, in combination, provide capabilities to provide functions not available in other, generally comparable designs. Fig. 1 shows salient details of the adapter design. One key element of the subsystem is that it provides a programmable signal processor (PSP) in combination with read/write RAM (random-access memory). Use of RAM permits the PC to change the nature of the adapter by loading different programs into the PSP RAM. Thus, the PSP subsystem performs a particular function at one time, but a completely different function at a different time. The adapter provides ports to a microphone and speaker connection, and with analog-to-digital and digital-to-analog conversion. These elements allow speech-processing code in the signal processor to perform speech functions via the microphone and speaker. The connection to (at least one) telephone line and a telephone are also provided. These permit the operation of telephony signalling functions and the speech functions from remote locations. The telephone connection is such that the telephone can be physically connected to the line or disconnected from it. This switch allows full telephony control to be exercised whether the user has the handset on-cradle or off-cradle. Further, this arrangement allows monitoring of signals from the telephone and telephone line independently. Alternatively, connecting the telephone directly to the line permits the telephone to be used in the normal manner. The hardware provides two ADC (analog-to-digital converter) and DAC (digital-to-analog converter) channels, each switchable between several ports. Simultaneous operation of these ports allows speakerphone operation, dialing of numbers regardless of the cradle status of the telephone handset, and simultaneous dialing while other operations, such as recording, are in process. The ADC and DAC are linear devices. This feature is significant when the signals are transmitted to or from the telephone or telephone line. A common switched telephone line is a "two-wire" device. That means that information flows in both directions simultaneously on the same media. One characteristic of telephone lines is that all reflect the incident signal back to the driving source, all alter the amplitude and phase characteristics as a part of the reflection process, and the reflection characteristics of each call are unique. For most calls, the amplitude of the reflected signal is much stronger than the level of the signal received from the remote end. Thus in full-duplex situations, such as where two individuals speak simultaneously, the signal arriving at the DAC is a mixture of the near...