Inverting bits
in [DSP]
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From: Tim Wescott on 2 Jan 2010 13:32 On Sat, 02 Jan 2010 12:27:47 -0600, Avier wrote: >>How many "storage bits" do you need to count to three? What other >>hardware? What help does knowing the clock frequency provide? >> >>Jerry >> >> > > > i rephrase the question , i need to innvert the every third bit of the > btstream > > what would be the solution Ask your prof for help? (hint: you can do it with a 7473 and a 7486) -- www.wescottdesign.com
From: Jerry Avins on 2 Jan 2010 14:14 Avier wrote: >> How many "storage bits" do you need to count to three? What other >> hardware? What help does knowing the clock frequency provide? >> >> Jerry >> > > > > i rephrase the question , i need to innvert the every third bit of the > btstream > > what would be the solution Hardware or software? Either way, count bits modulo three and invert the bit whenever the count is, say, zero. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
From: Jerry Avins on 2 Jan 2010 14:23 Vladimir Vassilevsky wrote: > > > robert bristow-johnson wrote: > >> that being said, it sounds like you need a counter. i'm sure someone >> has a nice compact divide-by-3 counter circuit laying around. it >> would need at least 2 flip-flops in it. > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > Nope. > > There is about a zillion of ways for making N-state flip-flop, i.e. > flip-flap-flop for 3 states, flip-flap-flup-flop for 4 states, etc. Deja vu! In first grade, students were allowed to go home for lunch. The rule changed when I began second grade. Everybody had to bring lunch and eat it in the gymnasium. On the second day of school, one of my classmates began to whimper. Ever solicitous, I asked him what was wrong. He answered, "I have to go to the bathroom." I said, "It's right over there. Lunchtime, you don't need to ask." He answered, "Somebody has to wipe me." Ever solicitous, I showed him how to do it himself. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
From: Tim Wescott on 2 Jan 2010 15:02 On Sat, 02 Jan 2010 14:23:01 -0500, Jerry Avins wrote: > Vladimir Vassilevsky wrote: >> >> >> robert bristow-johnson wrote: >> >>> that being said, it sounds like you need a counter. i'm sure someone >>> has a nice compact divide-by-3 counter circuit laying around. it >>> would need at least 2 flip-flops in it. >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Nope. >> >> There is about a zillion of ways for making N-state flip-flop, i.e. >> flip-flap-flop for 3 states, flip-flap-flup-flop for 4 states, etc. > > Deja vu! In first grade, students were allowed to go home for lunch. The > rule changed when I began second grade. Everybody had to bring lunch and > eat it in the gymnasium. On the second day of school, one of my > classmates began to whimper. Ever solicitous, I asked him what was > wrong. He answered, "I have to go to the bathroom." I said, "It's right > over there. Lunchtime, you don't need to ask." He answered, "Somebody > has to wipe me." Ever solicitous, I showed him how to do it himself. > > Jerry Which just goes to show that school is for showing us those bits of life that our parents never thought to let us in on. The next comment will be cynical, and will make this degenerate into politics or social commentary, so I'll try to resist. -- www.wescottdesign.com
From: Eric Jacobsen on 2 Jan 2010 15:02
On 1/2/2010 11:00 AM, Avier wrote: > suppose if am having a clock frequency of 60 Mhz and i want to invert > every third bit that is inverting signal at 20Mhz . what could be the > best solution in terms of least number of storage bits . > > i think a counter can be used but how many storage bits we will count > it? > > any other solutions The answer depends on what you're trying to optimize. Do you just want a solution that works? Or a solution with the minimum number of states? Or a solution with the minimum hardware complexity? Or a solution with the least power consumption? Or a solution with the least number of software instructions? Three D-flops connected in a ring will do it. I don't know if that will satisfy your professor, though. -- Eric Jacobsen Minister of Algorithms Abineau Communications http://www.abineau.com |