[Hackrf-dev] RF path: replacing MAX5864 with MAX5865

Frank Liu frank.zijie at gmail.com
Wed Sep 20 11:17:24 EDT 2017


I see. Many thanks for all your help.

Hopefully my last question - were you able to fiddle with the filter mode
(bits D3:D2, LPF register 1) i.e TX LPF vs RX LPF? My thinking is that if
we configure the filter to operate for RX only we may still be able to at
least transmit a higher BW signal without requiring a different chip.

On Sep 20, 2017 10:23 PM, "Michael Ossmann" <mike at ossmann.com> wrote:

> I've observed no change of behavior when setting LPF disabled in register
> 2.
> Specifically I have looked for aliasing.
>
>
> On Tue, Sep 19, 2017 at 06:18:27PM -0700, Frank Liu wrote:
> >
> > Wow, that is a bit of a bummer. Just to make sure we're on the same page,
> > I'm referring to page 20 of the MAX2837 datasheet:
> > https://datasheets.maximintegrated.com/en/ds/MAX2837.pdf. Is it just
> > straight up wrong?
> >
> > On Tue, Sep 19, 2017 at 5:56 PM, Michael Ossmann <mike at ossmann.com>
> wrote:
> >
> > > Frank,
> > >
> > > I've tried without success to disable the baseband filter.  If it
> works for
> > > you, please let me know how you did it.
> > >
> > > Thanks,
> > >
> > > Michael
> > >
> > >
> > > On Tue, Sep 19, 2017 at 05:53:56PM -0700, Frank Liu wrote:
> > > >
> > > > Thanks for the quick reply! For the MAX2837, we were actually
> thinking of
> > > > just disabling the baseband filter via the LPF register. We'll be
> > > operating
> > > > in transmit mode for most of the time anyway, and we can apply
> digital
> > > > filters to any received signals we need to clean up.
> > > >
> > > > --Frank
> > > >
> > > > On Tue, Sep 19, 2017 at 10:39 AM, Michael Ossmann <mike at ossmann.com>
> > > wrote:
> > > >
> > > > > Frank,
> > > > >
> > > > > Yes, you can replace MAX5864 with MAX5865.  However, you may still
> run
> > > into
> > > > > bandwidth limitations from the MAX2837 (31 MHz maximum baseband
> filter
> > > > > bandwidth) and SGPIO (our implementation tops out at about 25
> Msps).
> > > > >
> > > > > Michael
> > > > >
> > > > >
> > > > > On Mon, Sep 18, 2017 at 06:58:19PM -0700, Frank Liu wrote:
> > > > > >
> > > > > > Hey folks,
> > > > > >
> > > > > > We're hoping to extend the existing HackRF design to support a
> wider
> > > > > > bandwidth. Looking at datasheets, it seems that we can simply
> > > replace the
> > > > > > MAX5864 (22Msps) with a MAX5865 (40Msps) with pretty much no
> change
> > > in
> > > > > > hardware design.
> > > > > >
> > > > > > Was wondering if anybody had tried this already. Our HackRF will
> be
> > > > > > "standalone", meaning that we won't be constrained by USB2.0's
> I/O
> > > speed.
> > > > > >
> > > > > > Thanks!
> > > > >
> > > > > > _______________________________________________
> > > > > > HackRF-dev mailing list
> > > > > > HackRF-dev at greatscottgadgets.com
> > > > > > https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
> > > > >
> > > > >
> > >
>
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