Lect1_ DSP.pptx
- 1. MODULE IV Digital signal processor: Digital signal processor and its design issues, evolving architecture of DSP, next generation DSP. Customizable processors: Customizable processors and processor customization, A benefit analysis of processor customization, use of microprocessor cores in SOC design, benefits of microprocessor extensibility.
- 2. DSP And Its Impact On Technology Book: Processor Design Systems On Chip Computing For ASICs And FPGAs
- 3. Introduction
- 4. • DSP is a relatively new science. It has its roots in a group of universities following the discovery (or rediscovery) of the Fast Fourier Transform (FFT) in the mid-1960s by Cooley and Tukey, • The only computing resources available were mainframe computers, it requires a significant number of multiplications and additions. •Because signal processing it was impossible to do any of the research in real time. The early beginning of DSP
- 5. An Algorithm For Machine Calculation For Complex Fourier Series
- 6. Earlier computer to do research in DSP
- 7. DSP community • With in last 30 years sharing of ideas between DSP research and • Earlier with the advancement, microprocessors were to do some simple DSP tasks in real time Mini computers and Array processors were state of DSP research community the choice • the art for • Breakthrough combination of that made the DSP possible hardware was the a microprocessor and a multiplier • in 30 circuit community and invention of transistor revolutionized the world with commercially available DSP
- 8. and general urpos computer o array rocessor so “That discipline which has allowed us to replace a circuit previously composed of a capacitor and a resistor with two anti-aliasing filters, an A-to-D and a D-to-A converter, and long as the signal we are interested in does not vary too quickly.” Dr. Tom Barnwell
- 9. A i t h l O l f ti bl t ff d Voice band modems Hard Disk Drives and 3D Graphics were successful commercial products using DSPs The DSP revolution • DSPs were primarily a university curiosity in the 1960s – a toy for university professors to play with In the 1970s, DSP became a military advantage The 1980s experienced the introduction of the cost-effective DSP • • The 1990s, which can best be described as the decade of consumer expansion Digital Cellular Phone can be the best example Now in 21st century DSP is every where •
- 10. voice communications digital e Impact on Society • The first wave of the revolution was, and continues to be, communications • • Analog wire-lined world of communications became digital voice communications digital • Industry moved from 2400 bps modems to 56K bps band modems • Digital Cell Phone everywher 802.11 DSL Bluetooth voice • • •
- 11. TV • The second wave of the revolution is entertainment • • • • • • Music Photo TV Games Radio Streaming Media, combination of Digital Communication and Digital Entertainment And all in the pocket same time •
- 12. without humane intervention • What could be the next wave of revolution • Transportation • It is a matter of time when your car will drive from point A to B without humane intervention Biomedical Science • Higher quality life of a deaf man with Cochlear implant Education • But there will be better uses in the classrooms as well • •
- 13. What is DSP ? Digital Signal Processing (DSP) is used in a wide variety of applications, and it is hard to find a good definition that is general. changing or analyzing information which is measured as discrete sequences of numbers TMS320C25 DSP
- 14. DSP Algorithm TMS320C25 DSP Example : Digital Filters (e.g. Digital FIR Filters ,...) Most share common features: •They use a lot of maths (multiplying and adding signals) •They deal with signals that come from the real world •They require a response in a certain time
- 15. Why DSP Processors? A Comparison : As shown ,DSP Processors are more efficient TMS320C25 DSP
- 16. TMS320C25 DSP Why DSP Processors? (Contd.) As in FIR Filters
- 17. Why DSP is different than other Processors
- 18. System Some Basic Characteristics System of a DSP • • • • • • • Sampled data system Intensive mathematics Real time Deterministic Interrupt handling Accuracy Special hardware
- 19. • Sampled Data system • The signal must be sampled at twice the max frequency in the signal known as Nyquist Freqency Intensive Mathematics • Most of the time in Signal Processing we do Filtering or Transforms • • Demand for lot of MAC operations Following is a simple filter equation • • For 100 tap FIR filter 100 MAC operations are needed For 25 1080p frames per Sec a 50 tap filter needs to do 2.5 million MACs per Sec for audio signal
- 20. Real Time • For every input sample there is an output sample • Latency, how much is the delay between input and its relative output • Easiest example is audio recording. Musician has an ear piece to listen himself and others. The delay should be less than 5ms to consider it to be real time Deterministic • Instruction execution time must be same every time independent of data or state of execution unit • Predictability to estimate the capability of DSP to meet the demands early in the design cycle
- 21. the principle that real time systems cannot be interrupted Interrupt handling • This feature was added with the concept that interrupts are entertained until the real time behavior is not effected to stick to the principle that real time systems cannot Accurate • Accuracy is signal dependent • Three basic concepts to know here are interrupted • • • SNR which is data accuracy. Simple relation is 6dB per bit Coefficient accuracy is important in filters Internal Accuracy
- 23. L H d t f th DSP l ith titi h Special hardware • To meet the needs of real time systems special hardwares that DSPs have include are • Loop Hardware as most of the DSP algorithms are repetitive such FIR or FFT Data memory management as DSP algorithms often rely on present and past values of input data Saturation logic to keep the numbers inside the bound. If result exceeds the bounds maximum +ve or –ve number is assigned • E.g. scale all the data and coefficients to keep the results with in +1 and -1. But multiple MACs may yield the result out of this bound so the concept of guard bits in accumulator was developed Multi-MAC units executing in parallel has increased the perforamance of DSP rapidly over the last couple of decades • • •