On Apr 15, 2:01=A0pm, Jean-Yves <no-pub-for-jypoc...@[EMAIL PROTECTED]
> wrote:
> In article
> <9591c2c7-93e1-4bbf-bd75-35bcfcfad...@[EMAIL PROTECTED]
>,
>
>
>
>
>
> =A0logicgeek <logic.analy...@[EMAIL PROTECTED]
> wrote:
> > > 8 channels is too low for a logic analyzer
> > > 16 is a minimum
> > > 34 is far enought
>
> > > you must count $500 for a complete logic ****t with some grabbers...!
>
> > > I never heard of this annie-usb before...
> > > but saw a lot of people around here happy with their logic****t
>
> > > so...make your choice !
>
> > > --
> > > Jean-Yves.- Hide quoted text -
>
> > > - Show quoted text -
>
> > What I like about the Annie-USB is that it comes complete with SMD
> > grabber clips that optionally would cost some extra money.
> > If you have the time go towww.janatek.com/annie-usbmain.htm. It
> > retails just below $500..My only concern thou is that it s****ts only
8-
> > channels. However they have a nice little article on their website
> > about evaluating logic analyzers and I must say that I agree with this
> > article in that I will rather buy 8 'good channels' with sufficient
> > buffer depth than 32 channels and anyway not be able to use them all.
>
> > The faq article is at:http://www.janatek.com/faqbuying
logic
analyzer.ht=
ml#6
>
> > I've talked to some people and most of them said that I should opt for
> > sufficient buffer depth. What is the feedback of those happy okes
> > using logic****t?
>
> the logic****t has a compression algorythm so that he can record days of
> datas. it only records when the data changes.
That is true. It only records when data changes, But when your data
never changes why do you need a logic analyzer, and when your data
actually changes even at a moderatly freqency your little buffer would
fill up in no time.
Come on, if data compression was the epiphany solution, why would any
developing company at all offer you a deep sampling buffer.
Data compression is much cheaper to develop and manufactured. Quote
article in Evaluation Engineering.
"Lossless signal compression is included in this product because
its basic memory depth is 2,048 S/channel. To conserve memory, the
LA1034 only records data
transitions. Lossless data compression relies on redundancy
within the data, which can be encoded to reduce storage requirements.
The amount of compression
possible depends on the nature of the data. For example, the
LA1034 datasheet quotes a 233:1 maximum compression ratio or a factor
of greater than eight
billion. This degree of compression is possible for a signal
starting with a single logic 1 followed by eight billion zeros. If
your signals typically consist of a few fast
pulses with lots of dead time, compression can be very useful.
However, for very active signals with a large number of transitions,
the effective compression ratio
will be small.
The reason Logic****t offers data compression rather than a larger
sampling buffer is that they only use the little onboard memory
available in the single FPGA in their instrument. (Quote article in
Evaluation Engineering)
"The LA1034's logic and memory are entirely contained within a
single FPGA," commented Harrison Young III, company CEO. "This keeps
the speed up and the
cost down compared with products having external memory
interfaces. The LA1034's efficient lossless compression algorithm
allows its buffer depth to be greatly
extended with no loss in signal integrity."
Makes sense to me. Larger buffer makes even more sense
> the annie usb record also when the data dont change which is a waste of
> buffer...
> and definitely 8 channels is not enought
>
> the logic****t with 34 grabbers (and channels) =A0is around $500
>
> the sufficient buffer depth is to compare with old logic analyzers that
> had only some ko of memory and that are unusable today.
> the logic****t has enought.
|
