[time-nuts] MV89A / MTI-260 / HP10811 carrier board

[Magnus Danielson]

Dear Gerhard,

I think you missed my point by reacting to the technology choice rather 
than the function I was proposing.

BTW, I write VHDL, assembler and C code as my daytime work, dealing with 
timing.

Cheers,
Magnus

On 02/26/2016 02:30 AM, Gerhard Hoffmann wrote:
> Am 25.02.2016 um 22:23 schrieb Magnus Danielson:
>> Interesting. I would consider the PICDIV such as that of TADD-2, which
>> has the benefit of producing a range of frequencies, so that a
>> suitable can be selected as matching the needs. I've found it very
>> useful property of the TADD-2, where I have my TADD-2s wired up to
>> output one of each. I also wired them to output the buffered variant
>> of the clock, which gives better measures compared to running the sine
>> straight into the counters.
>
> I have never used PICs and given their life cycle it's a bad time to
> jump on the train.
> Not now when I'm just converting everything to ARM. OTOH I have used
> Xilinx since they exist
> and this board is more or less a cleanup of things that are already there.
>
>
> This here is all it takes for 10 and 100 MHz oscillators:
>
> ----------------------------------------------------------------------------------
>
> -- Company:         Hoffmann RF & DSP
> -- Create Date:    09:09:37 08/08/2012
> -- Module Name:    pps1_generator - Behavioral
> -- Target Devices:   X2c64A-5VQ44
> -- Additional Comments:   Free firmware under BSD license
> ----------------------------------------------------------------------------------
>
> library IEEE;
> use IEEE.STD_LOGIC_1164.ALL;
> use ieee.numeric_std.all;
>
> entity pps1_generator is
>      Port(
>          clk         : in  STD_LOGIC;
>          RunAt100MHz : in  STD_LOGIC;
>          pps1_out    : out STD_LOGIC;
>      );
> end pps1_generator;
>
> architecture Behavioral of pps1_generator is
>      signal tctr       : integer range 0 to 99999999;
>      signal pw_ctr     : integer range 0 to 199999;
>      signal cycle_done : boolean;
>      signal pw_done    : boolean;
>
>      function bool2sl(b : boolean) return std_logic is
>      begin
>          if b then return '1'; else return '0'; end if;
>      end function bool2sl;
>
> begin
>
>      u_div : process(clk) is
>      begin
>          if rising_edge(clk) then
>              cycle_done <= (tctr = 0); -- pipeline the comparator
>
>              if cycle_done
>              then
>                  if RunAt100MHz = '1' then
>                      tctr <= 100000000 - 2; -- divide by 100 Meg
>                  else
>                      tctr <= 10000000 - 2; -- divide by 10 Meg
>                  end if;
>
>              else
>                  tctr <= tctr - 1;
>              end if;
>
>          end if;                         -- rising_edge()
>      end process u_div;
>
>
> -- produce the standard 20 usec pulsewidth
>      u_pulsewidth : process(clk) is
>      begin
>          if rising_edge(clk) then
>              if cycle_done then
>                  if RunAt100MHz = '1' then
>                      pw_ctr <= 19999;
>                  else
>                      pw_ctr <= 1999;
>                  end if;
>
>              elsif pw_ctr /= 0 then
>                  pw_ctr <= pw_ctr - 1;
>              end if;
>
>              pps1_out <= bool2sl(pw_ctr /= 0);
>
>          end if;                         -- rising_edge()
>      end process u_pulsewidth;
>
> end Behavioral;
> -------------------------------------------------------------------------------------------------------------
>
>
>
>
> I have also a version that fits into 2 chips, runs at Osc = 200 MHz and
> produces a fixed 1/10/100/1000pps and another pps that can be shifted
> against the first one in 5nsec steps over > 1 second.
> It also provides control for a Micrel ECL chip that does the ps
> interpolation
> between the 5 ns steps.
>
> It has a shift register interface that is controlled by a Beagle Bone Black
> under Debian Linux, so network access is free.
>
> Ideal for testing ranging systems and TICs / TDCs, but it still needs
> some software.
>
>>
>> The power-supply input didn't look all that clear. It would be handy
>> if a single input could be used.
>>
> It can run on  -5...-8V (for the opamps) and +12V for Morion and MTI;
> the HP10811 needs 20V or so
> for its heater. In this case the 12V is made from the 20V. I do not want
> a switcher there.
>
>
>
>> I could probably have use for several of these boards.
>>
> Me too. I have recently decremented the number of available Lucent REF 0
> plug-ins quite substantially.
>
> (BTW: The Lucent REF 1 units with GPS are completely sold out for good,
> I have asked.)
>
> The idea is to lock 8 or 16   5 MHz MTI-260s to something long-time
> stable and see
> how far I get wrt phase noise when I combine the outputs.
>
> Seems to be more promising than that promiscuous coupled resonator stuff
> that was promoted recently. It is even somewhat tunable.
>
> I like throwing repetitive hardware at problems when I get sth. in return.
> Like my 220pv/sqrtHz preamp with 20 low noise opamps averaged.
>
> regards, Gerhard, DK4XP
>
>
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