Buu zdjecia brak... A co do mylnego oznaczenia na stronie, to niezupelnie jest tak - w jednym miejscu opisuja poprostu oba modele (cholera wie czemu).
Co do XEM to nie tyle szkoda, ze nie wyszlo... To jest masakra! :D Czytalem kiedys artukul o wrazeniach z targow, gdzie ow model byl prezentowany. W 1983 roku - zapuszczono glos spiewaczki operowej (!) po czym na zywo zmieniono barwe dzwieku uzyskujac glos meski...
Ale co sie dziwic - cycat:
"The chip was basically a bank of 64 oscillators with onboard ramp generators for amplitude and frequency. It was very much based on Hal Alles synthesizer that I believe (my memory is faded) ended up as Korg synth. Hal was at Bell Labs I believe and published his design, we were very much influenced by this and used lots of his tricks, for example the one where he avoids a multiply by pulling two samples out of a sine table and differencing them.
Although 64 oscillators were available, only 8 frequency ramps were provided as they were harder than amplitude ramps. (This turned out to be one of my errors, I believe.) So the idea was that a 'voice' had a single frequency generator and then some arbitrary number of oscillators attached as harmonics, each with its own amplitude ramp generator but slaved to a multiple of the fundamental frequency. As a result, Amy was awesome at single voice with all 64 harmonics attached to it. This is basically high quality additive synthesis and almost has to sound good as long as the amplitudes are right. Further, the amplitudes are easy to get from an actual recording via sort-time FFT analysis. When a piece of audio is analyzed for this purpose you have to be a little careful in the case of vibrato or glissandi and this was the focus of my work at CCRMA, following up on the landmark work of Andy Moorer.
To keep the ramp generators compact, amplitude and frequency ramps were done in log space, that is, dB and semitones. I can't remember the resolution we used, Sam would probably remember. This required a log to linear conversion, we used a table lookup as I remember. Another advantage is the compact communication over the 8 bit bus to the microcontroller (we were expecting an 8051-like part).
The controller transmitted both a target (amplitude or frequency) and a slope. Amy then ramps the appropriate parameter according to the slope commanded until it hits the target.
Clearly this sum-of-sinusoids or additive synthesis approach is flexible and efficient for narrowband voices such as most musical instruments and singing voice. However, for wideband instruments such as cymbals or unvoiced speech Amy had the ability to use some of the 64 oscillators in a wideband mode. In this mode random noise was generated using maximal-length-sequence generation which was filtered to create variable bandwidth noise. The noise was then used to modulate the oscillator, shifting the center frequency of the noise to that of the oscillator. It worked ok and was a fairly unique feature, one of the main claims of the patent application we filed."
8O
