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This appendix explains how the Speak and Spell speech data was packed in the ROM code. It takes the coded data for a spoken word and shows the process of packing it into a set of data that would be found in the ROM code.


A detail worth spending time on is how the speech data was packed into the ROM. An example of how it was done is shown in the following four figures (Figures 1 - 4). Figure 1 is an overview of the packing algorithm that I put together for a presentation on this topic. Figures 2 and 3 show the coded data for the word "cage". The coded data was taken from the information at the top of Figure 4. When the packing process was completed as shown in Figures 2 and 3, the resulting data matches the information in the bottom part of Figure 4. I am relatively certain that just using the four figures won't help much in understanding the process. So, I will pull excerpts from Figures 2 and 3 and use them to explain the process.

An overview of how the encoded speech data was stored in memory.

First page of encoded data for the word "cage" (frame number, energy, repeat, pitch, K1 - k6).

Page 2 of encoded data for the word "cage" (K7 - K10)

Computer printout showing the intitial encoded data and the final packed data for the word "cage"

The top set of data in Figure 4 is the parametric data for the word "cage". The first column is the frame number, the second is the energy level the third column is the pitch period, and the remaining columns are the reflection coefficients going from K1 to K10 starting from the left going to the right. The bottom set of data is the final packed data for the encoded word.

I have taken the first five frames of data from Figures 2 and 3 and put them in Table 1. It will be easier to see the data and explain the process using this table rather than attempting to work through the hand written figures.

First 6 frames from figures 1 and 2
Frame Energy Rpt Pitch K1 K2 K3 K4 K5 K6 K7 K8 K9 K10
8 1001 0 00000 10101 10110 0110 0110 - - - - - -
9 0110 1 00000 - - - - - - - - - -
10 0110 1 00000 - - - - - - - - - -
11 1101 0 01010 10010 10000 0101 0101 0110 1011 1010 101 011 010
12 1101 1 01011 - - - - - - - - - -
13 1101 0 01100 10110 10001 0111 0100 0000 1010 1011 110 100 011

Notice that frames 8 - 10 are unvoiced with frames 9 and 10 being repeated copies of frame 8. The "1" in frames 9 and 10 indicate that they are repeated frames. Frames 11 - 13 are voiced frames. Frame 12 is a repeat frame. Referring back to figure 1 you can see that an unvoiced frame (frame 8) only has the first four reflection coefficients (K1 - K4), where a voiced frame has all ten coefficients (frames 11 and 12). In all cases the repeat frame has no coefficients and the repeat flag is set to a "1".

The process consists of several steps

  1. Encode the parameters into binary
  2. Repack the binary numbers into hexadecimal
  3. Bit reverse each hexadecimal number
  4. Reverse the order for each pair of hexadecimal numbers

If I take the binary sequence for Frames 8 through 13 I get this sequence of bits:

1001 0 00000 10101 10110 0110 0110 . 0110 1 00000 . 0110 1 00000 . 1101 0 01010 10010 10000 0101 0101 0110 1011 1010 101 011 010 . 1101 1 01011 . 1101 0 01100 10110 10001 0111 0100 0000 1010 1011 110 100 011

Notice that I have inserted a "." to separate each of the frame sequences and have used a blank to separate the 13 parameters within each frame. The next task is to reformat the bits into hexadecimal. the bits for each hexadecimal number are shown in parenthesis below:

(1001) (0 000)(00 10)(101 1)(0110) (0110) (0110) . (0110) (1 000)(00 . 01)(10 1 0)(0000) . (1101) (0 010)(10 10)(010 1)(0000) (0101) (0101) (0110) (1011) (1010) (101 0)(11 01)(0 . 110)(1 1 01)(011 . 1)(101 0) (0110)(0 101)(10 10)(001 0)(111 0)(100 0)(000 1)(010 1)(011 1)(10 10)(0 011) [1011]

I have put brackets around the last nibble to indicate that it came from frame 14. It was necessary to create an even number of nibbles so that the process could be completed on this example. Now that the binary sequence has been organized into nibbles, I can use Table 2 to convert the nibbles into hexadecimal.

Hexadecimal table
Decimal Binary Hexadecimal Bit Reversed
0 0000 0 0
1 0001 1 8
2 0010 2 4
3 0011 3 C
4 0100 4 2
5 0101 5 A
6 0110 6 6
7 0111 7 E
8 1000 8 1
9 1001 9 9
10 1010 A 5
11 1011 B D
12 1100 C 3
13 1101 D B
14 1110 E 7
15 1111 F F

In hexadecimal it would look like: 90 2B 66 66 81 A0 D2 A5 05 56 BA AD 6D 7A 65 A2 E8 15 7A 3D

Bit reversed would look like: 90 4D 66 66 18 50 B4 5A 0A A6 D5 5B 6B E5 6A 54 71 8A E5 CB

Finally doing a pair wise nibble switch it would look like: 09 D4 66 66 81 05 4B A5 A0 6A 5D B5 B6 5E A6 45 17 A8 5E BC

If this sequence is compared to the bottom data set of Figure 4 it will be comforting to see them identical. Obviously we could have completed the whole word to verify that all of works. But, then, that is what Figures 2 and 3 attempted to do.

You may notice that I have ignored the creation of and use of the encode and decode tables. These tables were created based on a specific professional speaker. For each of the coefficients a test data set was used to reduce all of the variations to a set of buckets. For example with K1 where there are five bits to define the value of the coefficient, the data set was split into 32 buckets ranging from the largest to the smallest. A median point was selected to be the value used for the decoder. As this was specific to each professional speaker and therefore to each version of the TMS028x it will not be presented. That part of the process is left to the student to figure out. And, yes, you may have noted that I didn't disclose how the spelling of the words was packed into the ROM along with the speech data. Another aspect left to the student to figure out.

Questions & Answers

how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Do somebody tell me a best nano engineering book for beginners?
s. Reply
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
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for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
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what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, The speak n spell. OpenStax CNX. Jan 31, 2014 Download for free at http://cnx.org/content/col11501/1.5
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