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               8bit AUDIO A/D CONVERTER DRIVER

                     VOICE.COM  ver 0.10

               Copyright (c) 1995 Haruya.Mori


Have the thought ever occurred to you that it would be
interesting if an HP100LX/200LX could record voice?
However, such an option doesn't seem to be available for
purchasing. For this reason, I tried to make a mike unit
that can be used by attaching it to the serial port of
the LX.

This mike unit gets its power from the signal line of the
serial port, therefore, it doesn't need a cumbersome
battery in the mike unit. If done skillfully, the unit
can be installed in a 5 cm case(diagonally measured). For
someone with great packaging techniques, you probably can
do it with a case the size of a matchbox(I cannot do it).

This archive contains the program VOICE.COM, which
controls such a mike unit. Using speed doubled
100LX/200LX, it can record and play
back voice up to the maximum sampling frequency of 15k Hz.
According to sampling theory, voice with up to half of the
sampling frequency, i.e., 7.5kHz can be recorded. For
recording of human voice, I think this sampling frequency
is sufficient. (by the way, the highest frequency for the
telephone is 3.4kHz.)

For a normal speed LX, I think you can only get to a maximum
frequency of 7kHz.

                        [How to use it]

Connect the mike unit(please refer to the circuit diagram shown
below to make it) to the serial connector. For those who normally
turn off the power to the serial interface, use SERCTL /w to
turn it on.

Since VOICE.COM uses 64KB memory segment from the free area for
recording, it ensures the memory limit is not exceeded. Thus,
as long as there is memory available, it can record for a long
time.

Syntax:

VOICE [option(s)] filename

        filename is the name of the PCM file used for
        recording. It records in PCM format without the 8bit. Since
        this is the same format as SDK used on the Macintosh, it can 
        be converted into WAV or various other formats, utilizing a 
        program like PCMCONV.COM by Mr. T.K.
        
        The option(s) are explained below. Either upper
        case or lower case letters are fine. Multiple
        options can be specified with a space in between.
        
-P     load and play back the file specified by filename
     
-A      record voice and save it in filename
        
-F      specify the sampling frequency for recording. 
       The valid range is 2000 - 15000 with the default being
        7800. If the -P option is used, however, the
        range becomes 2000-44100. If you use a standard
        LX unit(not speed doubled) and don't specify a
        number below 7000, the system might freeze(not
        verified).

-C      specify interrupt cycle for playback. The valid range is 40
        - 255. If the number is small, noise is reduced.
        However, if the number is too small, Playback
        noise will increase and fidelity will be deteriorated. The default 
        is 51. For non speed doubled unit, If a larger number is not
        specified, the unit might freeze(not verified).
        
-V     specify playback volume. The rang is 1 - 100 with the
        default at 10. If a too large number is used, the sound becomes 
        chopped and is difficult to listen to.
        
        If -R as well as -A option are not specified, the
        unit comes into the dialogue mode.
        
        In this state, if the R key is pressed, the unit
        comes into record-ready mode. If the space key is
        pressed, recording starts. As long as there is
        memory, the recording will continue until a key
        is pressed.
        
        After the recording, press the P key to play it
        back. Press any key to interrupt the playback.
        
        In case the recording level is low and thus
        difficult to understand, press the L key to
        increase the volume by 4 times. However, if the
        recording level is too high, the sound will
        become distorted and difficult to listen to.
        
        If the S key is pressed, the voice will be saved
        to the file specified during start-up.
        
        Press the Q key to terminate VOICE.COM. Please be
        cautious since the recording will be lost if it
        is not saved.
        
        
        
                        [Circuit Diagram for Mike Unit]


Please refer to the following diagram to make the mike unit. Since 
there are many parts with polarity, please be careful during construction.



                        [Table of Parts]

Part Symbol  Part Name  Manufacturer    Note

IC1  HD14069UB HITACHI  Equivalent part from other company can be 
                        used. Since a digital IC is used
                        as an analog amp, it may not work
                        well sometimes. The UB type must
                        be used. The B type might run the
                        risk of oscillation.
                                         
IC2          TLC549I    TEXAS    8bit series output A/D converter.
                        INSTRU-   TLC548I  can also be used.
                        MENTS

IC3          TL431C     TEXAS    shanto(?) regulator
                        INSTRU-
                        MENTS

MIC1         WM55A103 MATSUSHITA 2-wire elctoreto condenser microphone(ECM).
                                 I think any generic 2-wire type ECM can be                                      used.
                              
SD1,SD2,SD3  1GWJ42    TOSHIBA  Silicon Schottky bi-diodes for current                                          regulation. Other diodes are also possible
                                if the voltage rating is above 20V and
                                current rating is 0.1 - 1A. However, diodes                                     with large joining capacity and large leak 
                                current cannot be used.

D1,D2        1S1588    TOSHIBA   Silicon diodes for small signal. Equivalent                                     types such as 1S2075 can also be used.

ZD1  Tseuna(?) diode   Tsuena   Voltage 6.2V  Power rating >250mW
C1   Aluminum electrolytic capacitor Static capacity  1uF voltage>6.3V
C9   Aluminum electrolytic capacitor Static capacity 10uF voltage>6.3V
C7   Aluminum electrolytic capacitor Static capacity 47uF voltage>6.3V
C5   non-polarity Aluminum electrolytic capacitor Static capacity 1uF
     voltage>6.3V

C2,C3,C4 ceramic capacitor Static capacity  22pF voltage>6.3V
C6       ceramic capacitor Static capacity 330pF voltage>6.3V
C8       laminated ceramic capacitor Static capacity 0.1uF voltage>6.3V

R12      Resistor      Resistance  680 Ohm  5% power>1/8W
R10,R11  Resistor      Resistance 4.7K Ohm 5% power>1/8W
R1,R13   Resistor      Resistance  10K Ohm 5% power>1/8W
R2,R4    Resistor      Resistance 22K Ohm 5% power>1/8W
R6,R8    Resistor      Resistance 22K Ohm 5% power>1/8W
R14      Resistor      Resistance 47K Ohm 5% power>1/8W
R9       Resistor      Resistance 100K Ohm 5% power>1/8W
R3,R5,R7 Resistor      Resistance 220K Ohm 5% power>1/8W

CN1      D-sub 9pin male connector

In addition, an universal substrate, a metal case,
screws, solder, wires, substrate space, etc. are needed.

Since this circuitry is constructed with a high-gain
mike amp, it is very susceptible to noise. Please do
your best to use a metal case and ground it as well.

Depending on where you live, it might be difficult for
you to get the parts. Just for reference, I ordered the
TLC549I from Ozawa Electrical Company in Tokyo and
bought other parts from the Silicon House in Nihonbashi,
Osaka. As for the way to order parts, it will be helpful
to look into the ads sections in the Electrical
Transistors or other technical journals.
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                       [Caution]
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As this circuitry is constructed with a half
analog circuitry, its performance will be affected by
the wavering wires. Moreover, if polarity and wires are
improperly connected, damage to parts can occur. Thus,
please exercise caution. Damage to the LX unit could
also occur due to mis-wiring although such possibility
is very slim.

Speaking of damage to the LX unit: sarcastically, the
most expensive parts tend to be damaged first. (This is
Murphy's Law for electronic circuits(^_^;))

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The playback algorithm of this program is based on the
one used in Mr.
Dejiyama's EVA ver. 2.31. I thank him for promptly giving
me the consent to use his algorithm.

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This softwareware is freeware. Haraya holds copyrights to
both the program and the circuit diagram.

With respect to the beta version, copying is prohibited.

The author will not compensate anyone for damages arising
from using the program, the documentation and the circuit
diagram appearing in this document. The construction of
the circuit and operation of the program are strictly the
responsibility of the user.

The author has no obligation to correct any defects or
mistakes in the program and documentation should they exist.
However, I will try to improve them if you contact me.


ver 0.10 Beta version first
public release


NIFTY-Serve PXW034030 HARUYA

