Gene A. Frantz

Digital signal processor trends

Advancements in digital signal processing technology are enabling its use for increasingly widespread applications. Developers will be challenged to use this processing power to its utmost, while creating new applications and improving existing ones.

Electronic apparatus for simulating singing of song

An electronic apparatus in which the operator inputs both the textual material and a sequence of pitches which upon synthesization simulates singing qualities. The operator inputs a textual material, typically through a keyboard arrangement, and also a sequence of pitches as the tune of the desired song. The text is broken into syllable components which are matched to each note of the tune. The syllables are used to generate control parameters for the synthesizer from their allophonic components. The invention allows the entry of text and a pitch sequence so as to simulate electronically the singing of a tune.

Design and implementation of numerical linear algebra algorithms on fixed point DSPs

Numerical linear algebra algorithms use the inherent elegance of matrix formulations and are usually implemented using C/C++ floating point representation. The system implementation is faced with practical constraints because these algorithms usually need to run in real time on fixed point digital signal processors (DSPs) to reduce total hardware costs. Converting the simulation model to fixed point arithmetic and then porting it to a target DSP device is a difficult and time-consuming process. In this paper, we analyze the conversion process. We transformed selected linear algebra algorithms from floating point to fixed point arithmetic, and compared real-time requirements and performance between the fixed point DSP and floating point DSP algorithm implementations. We also introduce an advanced code optimization and an implementation by DSP-specific, fixed point C code generation. By using the techniques described in the paper, speed can be increased by a factor of up to 10 compared to floating point emulation on fixed point hardware.

The Texas Instruments TMS320C25 Digital Signal Microcomputer

Capable of 10 million operations per second, the newest member of the TMS320 family can serve as an inexpensive alternative to bit-slice processors or custom ICs in digital signal processing applications.

Design case history: Speak & Spell learns to talk

Describes how a hand-held, low-cost electronic spelling aid with a speech output was designed. A major problem was the synthesis of speech of a quality acceptable to the consumer.

Text-To-Speech Using LPC Allophone Stringing

A low cost voice response system is presented, which performs text-to-speech conversion of any English text. The system is built around an LPC synthesizer chip and a microprocessor. Text-to-allophone rules are used to convert an input string of ASCII characters into allophonic codes. LPC parameters are then drawn from an allophone library, which takes very little storage space, and concatenated using a fast and simple algorithm to produce natural sounding speech.

Signal Core: A Short History of the Digital Signal Processor

I was in high school in the mid-1960s when the theories of digital signal processing were first discovered-or rediscovered, depending on whose story you accept. It was in the early 1970s when I heard of the phenomenal things digital signal processing could do in communications. I was at Texas Instruments (TI) in the calculator division, finishing my masters degree, when I was introduced to the theories of digital signal processing from a textbook titled Digital Signal Processing by Oppenheim and Schafer. That was in 1977.

On Voice Characteristics Conversion

Text-to-speech systems available today generate virtually unlimited speech from a prestored component sounds library, which is frequently created from a male voice. A major reason for that is due to the low pitch profile in the male voice. For example, the speech analysis software and commercial synthesizers seem to work more accurately and better with the male voice than the female voice. To overcome the analysis and synthesis problem on the female voice and to provide the choices of having more than one sex of voices output from a text-to-speech system, some means of voice characteristics conversion is needed. To do so, it is important to first understand what parameters in speech define the perception of different sex. An attempt is underway herein to first study these parameters and then to learn to adjust them so that the voice of one sex can be converted to another or from one voice character to another. The voice characteristics conversion technique described herein is best suited for speech systems either a text-to-speech or analysis-synthesis (meaning record-playback) using LPC synthesizers.

Ultra-Low Power Signal Processing [DSP Forum]

This IEEE Signal Processing Magazine forum discusses the latest advances and challenges in ultra-low power (ULP) signal processing (SP). The forum members bring their expert insights to issues such as design requirements and future applications of ULP SP systems.

The Application of a Synthesis-by-Rule System to Singing

Much has been accomplished in the area of speech technology in order that machines can talk to people. Various stringing techniques such as phoneme, allophone and diphone have been demonstrated to give those machines virtually unlimited vocabularies. The subject to be covered in this paper is not a new speech construction technique, but how a construction technnque can be combined with a speech synthesizer to allow the machine to sing. The system which will be discussed uses linear predictive coding (LPC) as its synthesis method and allophiones as its constructoin technique. In this paper, each segment of the system will be discussed in some detail.