Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Lasse Langwadt <llc@fonz.dk>
Newsgroups: sci.electronics.design
Subject: Re: DDS, again
Date: Thu, 12 Dec 2024 01:05:50 +0100
Organization: A noiseless patient Spider
Lines: 33
Message-ID: <vjd9cu$1pk9k$1@dont-email.me>
References: <lcthlj9gl86227o6hrc4sidglalkak4qj9@4ax.com>
 <vjc2r0$1i2il$1@dont-email.me> <36gjljpv1p6l0es2klp4as4e1oblolhh71@4ax.com>
 <vjctot$1n9s6$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Injection-Date: Thu, 12 Dec 2024 01:05:51 +0100 (CET)
Injection-Info: dont-email.me; posting-host="fc34fe6059a1898f0f115bdbccbead91";
	logging-data="1888564"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/16UxoJABIiPMYuq+R3bMzmp+jvNH3JIE="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:en9gLtxxO01yemNr5Vlssrof8mk=
In-Reply-To: <vjctot$1n9s6$1@dont-email.me>
Content-Language: en-US
Bytes: 2471

On 12/11/24 21:47, Klaus Vestergaard Kragelund wrote:
> On 11-12-2024 17:49, john larkin wrote:
>> On Wed, 11 Dec 2024 14:07:45 +0100, Klaus Vestergaard Kragelund
>> <klauskvik@hotmail.com> wrote:
>>
>>> On 11-12-2024 03:38, john larkin wrote:
>>>> I have been unsuccessful in getting LT Spice to simulate a DDS
>>>> frequency generator. It's bad enough trying to make the NCO part, but
>>>> whenever I get close it stalls or throws convergence errors.
>>>>
>>>
>>> I think you have the funds to buy Cadence Pspice. It has auto
>>> convergence build in. It's seldom I see problems with convergence after
>>> they added that feature.
>>
>> LT Spice is usually pretty good. It just didn't like my trying to make
>> a 32-bit phase accumulator with an analog circuit.
>>
>> I once fixed a convergence problem by adding one resistor to the
>> circuit. 1K, one ended grounded, the other end open.
>>
>> LT is horrible with digital stuff. Imagine making a 32-bit phase
>> accumulator with its parts. There isn't a screen big enough.
>>
>> Qspice is I hear better at mixed-signal sims.
>>
>> I can always have one of my kids Matlab the hard stuff.
>>
> If you buy Pspice Advanced, you can run c++ code in each time step, or 
> whatever timestep you like. I am doing that to simulate a digital SMPS 
> in spice

qspice and also run c++ or verilog modules