generating a clock signal with a SCL4046BE4 and sending that into a HEF4017BE

Discussion in 'General Electronics Chat' started by Joster, Nov 20, 2013.

  1. Joster

    Thread Starter Member

    Jun 12, 2013
    95
    0
    Seasons Greetings!!


    My question is about generating a clock signal with a SCL4046BE4 and sending that into a HEF4017BE on input pin 14. I want to use output pin 6 to divide the frequency. I have this set up and have been through the connections thoroughly. I have verified I have clock signal going in at about 400kHz but I don't have anything on any of the outputs. I have verified 5.13 V DC at pin 16 and grnd at pin 8. Is there anything else that should be connected?


    Thanks a ton!!!


    Joe
     
  2. Joster

    Thread Starter Member

    Jun 12, 2013
    95
    0
    correction **********SCL4046BE
     
  3. rogs

    Active Member

    Aug 28, 2009
    279
    37
    Assuming this is for your kick drum experiment?........to test that the 4017 is working as a divider, pins 15 and 13 will need to be connected to ground, as well as the clock into pin 14.

    As I mentioned in my post on your 'EPROM' thread, I've found a simpler way to control the counter.
    I tried the 4046 approach with a stripboard prototype, and had some problems trying to run the VCO as a clock reliably. For some reason , the capacitance of the stripboard tracks caused problems with the VCO timing components.
    Bit surprising --I've been able to run other clock circuits around !MHz on stripboard without to many problems in the past....... must be something different about the 4046 VCO circuitry?....

    So I had another look at the circuit, and decided that as the 4040 counter advances on the falling edge of the clock, then I could use a simple inverter to separate it from the DAC latch enable control.

    So I changed my prototype to run with a simpler clock and sequencer. Copy of my new circuit (which I have built ... so I know it works!) is attached, if it's of any use?...

    You'll also note that I've modified the trigger circuit. Helps in two ways. It means you can connect to an external trigger without having to risk CMOS static damage on the input, and it adds a de-bounced 'normally closed' input to the monostable, to help prevent false triggers.

    I've tried it all out, and it seems to work quite well -- although as it only uses a simple linear 8 bit DAC, the concept of the noise shaped dither I mentioned earlier needs to be investigated further. Hopefully shouldn't be too much of a problem with a simple kick drum sound!....

    Edit: couple of sample sounds from my first prototype here (each file is about 1MB) :

    sample 1

    sample 2

    each file is a 16 bit wave file recording of the unit's audio output (which is only 8 bit of course...)

    A picture of my stripboard prototype, built around this circuit is attached......still experimenting at the moment.....
     
    Last edited: Nov 21, 2013
  4. Joster

    Thread Starter Member

    Jun 12, 2013
    95
    0
    That circuit look great...nice job!

    You are really into this thread! I really appreciate all your input. I will try grounding those pins.

    You must do this kind of thing in your day job?
     
  5. rogs

    Active Member

    Aug 28, 2009
    279
    37
    Used to! :) ..Or rather something similar. Worked on 8 bit automatic speech systems in the 1980s (when 8 bit was all anyone could afford!) and did some work on using analogue companding, to improve the dynamic range of 8 bit systems.

    It's all largely academic these days... it's all 16 or 24 bit (understandably).. but I have a friend who wants to build a simple (and I mean simple!) drum machine using LinnDrum type sounds......which of course were 8 bit!

    So when I saw this thread, I thought maybe some of what I was thinking about might be useful here as well....

    As I mentioned, I'm really interested in finding more out about noise shaped dither, but I'm finding hard to find anything on how 8 bit 'wav' files are read to interprete the noise components from within the data.

    Loads out there on 'dither' noise theory, but nothing so far on how the actual wav files are decoded on playback... still looking...
     
  6. Joster

    Thread Starter Member

    Jun 12, 2013
    95
    0
    Cool! That must have been an interesting job! Thanks for the pin 13 and 15 ground tip. Worked perfect.....on to setting up the counter.....

    Talk soon!

    Joe
     
Loading...