On-Line #29 24 марта 1996

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Iron - ADC in bipolar mode conversion. Audio interface "Sound Driver - 1".

                 IRON


(C) L.D.E. SOFT


   If you remember, I mentioned last issue of the treatment of 
bipolar ADC. So, this is a regime under which an analog signal 
remembered as a positive sinusoid (classical kovoks) as well as 
a negative sine wave. And as you know from physics, audio 
signal is a bipolar sine wave, so when using the bipolar mode 
the sound is transmitted in a more lively and milder form. But 
to realize such a regime have little ADC in bipolar mode 
conversion, as all simple scheme DAC (kovoksov) work only in 
unipolar mode ... Conclusion: need circuit DAC, capable of 
converting recorded in bipolar mode, the digital signal into a 
normal bipolar sinusoid. Although the scheme is a bit 
complicated, this sounds just a DAC great! But there again the 
weaknesses (?): Bipolar power, plus high-precision reference 
voltage and an increase consumption of memory to record digital 
readout. 


   Scheme of DAC, operating in bipolar mode:

                                            + Uop
                                            > 15 in

                                                   > 15c

                  D1 R1-5k

            KR572PA1A K140UD20
                                 R2 D2
Obshy <13 D0 DA January 15 ■>
General <12 - D1 Uop 2
K D0 <11 D2 16 March 1912
K D1 <10 - D3 Ros 13
K D2 <9 - D4 I1 January 1914
K D3 <8 - D5 4
K D4 <7 - D6 + Un 14
K D5 <6 - D7 I2 2
K D6 <5 - D8 R3 4>
K D7 <4 - D9 0V May 3
                                      June 10> Exit
                               7 ■
R1-5k (01%) 8
R2, R3-10kOm 9
D1-K572PA1A (B)
D2-K140UD20
Note: R1, R2 are used for accurate installation of "0" at the 
DAC output, in the absence of input data.



   And now I want to offer you a long-awaited scheme 
mnogonaslyshannogo audio interface SOUND DRIVE - 1, developed 
by the Novosibirsk group of hackers FLASH inc. 


   Here is the scheme only the left channel. Why - see below.


                 Left channel output <
                          <
            R-matrix 4.7 to D2 C1
      D1 to + 5 volts. K572PA1A (B)

       KR580VV55 <13 R1 R2

                                         D0 DA 15 Vop

          IO 12 D1
D0 <34 D0 DB0 November 18 D2 Roc 1916
D1 <33 D1 DB1 Oct. 19 at D3 +5.
D2 <32 D2 DB2 Sept. 20 D4 I1 1>
D3 <1931 D3 DB3 August 21 D5
D4 <30 D4 DB4 July 22 D6 + Un 14 Gen.
D5 <29 D5 DB5 June 23 D7 I2 2>
D6 <28 D6 DB6 May 24 D8
D7 <27 D7 DB7 April 25 D9 0V 3

                                                       C2

              0V 7 + 5 volts.
A4 <9 A0 + Un 26 13 R3 R4

                                         D0 DA 15 Vop
A5 <8 A1 12 D1
 R5 DC0 November 14 D2 Ros 16

   6 ■ CS DC1 Oct. 15 at D3 +5.

  +5 DC2 September 16 D4 I1 1>

   5 ■ RD DC3 August 17 D5

            DC4 July 13 D6 + Un 14 Gen.

  36 ■ WR DC5 June 12 D7 I2 2>

            DC6 May 11 D8

  35 RS DC7 April 10 D9 0V 3



           D4 _____ D3

   2 ■ Jan. 1> RESET (K Z-80, 26n)


                > To the 35 foot VV55 right channel (reset)

           D5 ____

    3 1 1> IORQ (K Z-80)

          2 __

                > WR (K Z-80) + 5
              D8.1
                         R6

  Decoder channels: 11
___ D6.1 6 ■ 10 A6 D8.2
CSL 9>

   6 ■ April 5 ___

           May 8 ■ 4> DOS

                                           3

                      1 ■ 2

   3 ■ 1 March D8.3> A3

          2

                    D7 13> A2

      D6.2 12 ■ 2> A1
                         1> A0
           ___

               > To the CSR (6N) VV55 right channel

List of radioactive elements necessary to build SOUND DRIV:
R1ЎR4 - 10 kOm.
R5, R6 - 1 kOm.
Rmatritsa (or kit) - 2,2 kOm to 10 kOm.
C1, C1 '; C2, C2'-1 mkF.
D1, D1'-KR580VV55A
D2, D2 '; D3, D3'-KR572PA1A (B)
D4 - K555LN1 (155.1533)
D5 - K555LL1 (155.1533)
D6 - K555LA3 (155.1533)
D7 - K555LE1 (155.1533)
D8 - K555LA4 (155.1533)


   I cite the scheme only one channel (left), as the scheme
and so was a very huge. In addition, the second (right) channel 
repeats left (except for the decoder ports - it one for both 
channels). Right channel signals are connected in parallel 
signals of the left (D0-D7, A4-A5, Reset, RD> +5 c) except for 
the signal sample (/ CS) and, of course, the audio outputs. 


   I published scheme SOUND DRIVE is not an original
Novosibirsk option scheme, but is only its full-scale 
counterpart, which is collected and felt I - LDE SOFT. The only 
thing I saw on the circuit drive - this is only the decoder. 
Therefore, some schematics may be slightly different that the 
work unit as a whole has no effect! 


   Well, now that I think about this scheme:


   Not long ago, as soon as I emerged from demonstrushki
Novosibirsk, losing Mouzon through kovoks, drive and the baby, 
the my PENTAGON'e 512 Turbo was already a LPT kovoks ...



   Having heard plenty of Mouzon, and having read crawls, I
wanted to collect SOUND DRIVE ... Schemes I, of course, was not
(And still does not), but it was the desire to listen to four 
channels of 8 bit of music. Write a letter FLASH'am was also a 
bummer, and I decided to gather himself a sort of drive. For a 
long time picking Novosibirsk program, I could not understand: 
at the ports where they put four kovoksa. There is something 
reminiscent of ports VV55, but not identical to the standard (# 
1F, # 3F, # 5F). 


   After much thought I decided to hang three kovoksa on its 
own, VV55 standard connection, and the remainder left on kovoks

Port # FB (LPT), connected in pairs audio output DACs. 
Naturally, we had to change the address to the ports on the 
SOUND DRIVE # 1F, # 3F, # 5F, # FB. When I finally learned, 
based on what made SOUND DRIVE, I certainly appreciated the 
thrift ... my options. And I also advise you: if you have your 
computer has a port K580VV55 then hang kovoksy at him, and the 
remaining channel hang either the LPT (# FB), or, in extreme 
cases, collect analog LPT interface (only IR23 + dishifrator 
for # FB). Thus, you not only save radio components. You do not 
have to collect greater individual schemes (advice from LDE).



   This concludes the description of passive ADCs and DACs, 
based on the method of successive approximation. Maybe going 
out my scheme of active musical card that does not spend the 
whole computing time Z-80. 

                         (C) L.D.E. SOFT
                          Denis 400-0436