SPR Classic Line Speech Quality Diagramm Robustness Diagramm Algorithmic Delay Diagramm Computing Complexity Diagramm Memory Usage Diagramm Availability Diagramm

SPR Vocoders 1200 bps

Classic | Robust

About Classic and Robust

SPR Classic ™ 1200 bps vocoder is based on Sinusoidal Pulsed Representation (SPR) model, where excitation signal includes mixture of pitch-harmonics, noisy and aperiodic impulses.

It allows to synthesize correctly any speech sounds, including mixed voiced+unvoiced and complex transients.

Additionally, choice of optimal quantization schemes and high algorithmic optimization provided superior characteristics of this vocoder in comparison with others for the same bit rate

We used ITU-T P.50 multilanguage speech base and ITU-T P.862 utility to estimate speech quality.

SPR Classic 1200 bps vocoder doesn't concede practically MELPe 1200 bps standard vocoder. Average PESQ is: 3.05 vs 3.10.

Moreover, all other characteristics of the SPR Classic 1200 vocoder excel considerably appropriate characteristics of the standard vocoder.

We passed encoded bit streams through AWGN channel simulator with various SNR and estimated quality of decoded speech.

SPR Classic 1200 shows strong superiority over MELPe 1200.

Time delay is very important characteristic of communication system. Algorithmic delay of vocoder does play determinative role in total delay. Well known, the delay more than 100 ms is not acceptable for normal conversation

SPR Classic 1200 provides 60 ms delay, MELPe 1200 - 103,7 ms.

Frame size is 40 ms (320 speech samples).

SPR Classic 1200 requires two times lower computing resources and shows strong superiority over MELPe 1200.

Only 16 MIPS versus 44 MIPS for TI's C55xx.

We have estimated and compared resources of SPR Classic 1200 bps vocoder for TI's C55xx DSP.

SPR Classic 1200 shows strong superiority over MELPe 1200.

SPR Classic 1200 bps vocoder is available right now as:

- Object Code for TI's C55xx DSP,
- DLL (Win32) for PC

Also it is available for any other DSP, RISC or general-purpose platform during two-three months.