>We want to get a medium end oscilloscope for lab use. The basic
>requirement is 1GHz bandwidth and 4-Ch. The budget is around
>US$15,000 or a bit more.

I would look at the Tek TDS4000 series, or the Tek MSO4000 series. The 6000 
and 7000 series would be overkill here I think.

We already have a mid-end XP based Agilent Infinium
>MSO8104A scope (1GHz, 4ch) and three low end Tektronix TPS2024 4ch
>isolated 200MHz scope. We are very disappointed on the TPS2024 as it
>is really quite bad for even the simple lab use. It seems to me all
>the low-end Tektronix are very bad for lab use.

Hmm, surprises me. I haven't used the TPS2024, but do have a TDS2024, with 
isn't isolated. It does do its job quite well I thought.

>We do not have any
>high frequency stuff and typical usage is to debug MCU firmware,
>analog circuit and DC/DC converters. The Agilent is fine but the
>analog performance is not up to expectation of my manager. I like its
>MegaZoom function very much.

This may be where the MSO4000 mixed signal unit may be of help then. I 
believe it has a decent size buffer allowing long captures that you can then 
zoom in on, and IIRC understands various protocols like I2C, CAN etc.

>I'd like to get the recommendation for the low end as well (200MHz,
>4Ch, around belowe US$6000).

In that range I would look at a Tek TDS3000 range, larger screen and finer 
pixels than the TDS2000 series. The B version also comes with an Ethernet 
port I believe. Can also be battery operated, but if you don't have a 
battery, the battery compartment has a nice tray for storing the probes. 

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist