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Question about FREQOUT — Parallax Forums

Question about FREQOUT

ArchiverArchiver Posts: 46,084
edited 2004-03-01 23:04 in General Discussion
My BOE-BOT manual uses statement such as

FREQOUT 0, 1, 41000, but according to the manual, highest frequency
is 32767.

They seem to contradict each other.

What is the real limit on frequency?

What is the side effect of a frequency higher than 32767? Anything?

Thank you.

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-03-01 18:32
    In a message dated 3/1/2004 1:17:45 PM Eastern Standard Time,
    basicstampede@y... writes:


    > FREQOUT 0, 1, 41000, but according to the manual, highest frequency
    > is 32767.
    >
    > They seem to contradict each other.
    >
    > What is the real limit on frequency?
    >
    > What is the side effect of a frequency higher than 32767? Anything

    Frequencies higher than 32767 are derived from harmonics. I have used all
    sorts of frequencies and have never observed any side effects/ I've never gone
    higher 41500 so I don't know what the upper limit is.


    Sid Weaver
    W4EKQ
    Port Richey, FL


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2004-03-01 18:35
    At 06:12 PM 3/1/04 +0000, basicstampede wrote:
    >My BOE-BOT manual uses statement such as
    >
    >FREQOUT 0, 1, 41000, but according to the manual, highest frequency
    >is 32767.
    >
    >They seem to contradict each other.

    The 32767 restriction is for the BS-2 and BS-2e. Other Stamps are capable of
    higher frequencies per the table in the PBASIC Stamp Manual.


    >What is the real limit on frequency?
    >
    >What is the side effect of a frequency higher than 32767? Anything?
    >
    >Thank you.
    >
    >
    >Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2004-03-01 18:42
    My question pertains to BS2 which comes with BOE BOT.

    The BOE BOT manual uses higher frequency than what is supposed to be
    the limit according to the BS manual for BS2.

    Where is the harmonics coming from?

    Thanks.



    --- In basicstamps@yahoogroups.com, Bruce Bates <bvbates@u...> wrote:
    > At 06:12 PM 3/1/04 +0000, basicstampede wrote:
    > >My BOE-BOT manual uses statement such as
    > >
    > >FREQOUT 0, 1, 41000, but according to the manual, highest
    frequency
    > >is 32767.
    > >
    > >They seem to contradict each other.
    >
    > The 32767 restriction is for the BS-2 and BS-2e. Other Stamps are
    capable of higher frequencies per the table in the PBASIC Stamp
    Manual.
    >
    >
    > >What is the real limit on frequency?
    > >
    > >What is the side effect of a frequency higher than 32767?
    Anything?
    > >
    > >Thank you.
    > >
    > >
    > >Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2004-03-01 18:53
    The output from FREQOUT is actually a string of variable-width square
    waves. If you filter the output you'll get a nice sine wave at the
    targe frequency. Mathematically, a square wave is composed of its root
    frequency and all odd harmonics. It turns out that when you tell the
    Stamp to FREQOUT at 38500 (modulation for an IR LED) that the harmonics
    generated are strong enough at that frequency to do the job.

    One of our staff engineers, Andy, has taken this even further and done
    some really neat frequency sweeping to do distance measuring with a
    BOE-Bot. Download the Robotics text for that.

    And, contrary to other posts, the upper end of FREQOUT is indeed 32767
    -- for all BASIC Stamps.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: basicstampede [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Kz-d88L99noaZFLUy5u3p3d5kRhnjNjED6u4PyE6SlRBH4niHP0DTqHMeXAHfuRRC6ll_B_vf0WQkZ4vBL6JFQ]basicstampede@y...[/url
    Sent: Monday, March 01, 2004 12:43 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Question about FREQOUT


    My question pertains to BS2 which comes with BOE BOT.

    The BOE BOT manual uses higher frequency than what is supposed to be
    the limit according to the BS manual for BS2.

    Where is the harmonics coming from?

    Thanks.



    --- In basicstamps@yahoogroups.com, Bruce Bates <bvbates@u...> wrote:
    > At 06:12 PM 3/1/04 +0000, basicstampede wrote:
    > >My BOE-BOT manual uses statement such as
    > >
    > >FREQOUT 0, 1, 41000, but according to the manual, highest
    frequency
    > >is 32767.
    > >
    > >They seem to contradict each other.
    >
    > The 32767 restriction is for the BS-2 and BS-2e. Other Stamps are
    capable of higher frequencies per the table in the PBASIC Stamp
    Manual.
    >
    >
    > >What is the real limit on frequency?
    > >
    > >What is the side effect of a frequency higher than 32767?
    Anything?
    > >
    > >Thank you.
    > >
    > >
    > >Bruce Bates



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  • ArchiverArchiver Posts: 46,084
    edited 2004-03-01 19:03
    I'm confused. If you say that the upper limit is 32767, then how
    does the statement FREQOUT 1, 1, 41000 even compile? Or does it
    actually do FREQOUT 1, 1, 32767 instead?

    Thanks.

    --- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
    wrote:
    > The output from FREQOUT is actually a string of variable-width
    square
    > waves. If you filter the output you'll get a nice sine wave at the
    > targe frequency. Mathematically, a square wave is composed of its
    root
    > frequency and all odd harmonics. It turns out that when you tell
    the
    > Stamp to FREQOUT at 38500 (modulation for an IR LED) that the
    harmonics
    > generated are strong enough at that frequency to do the job.
    >
    > One of our staff engineers, Andy, has taken this even further and
    done
    > some really neat frequency sweeping to do distance measuring with a
    > BOE-Bot. Download the Robotics text for that.
    >
    > And, contrary to other posts, the upper end of FREQOUT is indeed
    32767
    > -- for all BASIC Stamps.
    >
    > -- Jon Williams
    > -- Applications Engineer, Parallax
    > -- Dallas Office
    >
    >
    >
    Original Message
    > From: basicstampede [noparse][[/noparse]mailto:basicstampede@y...]
    > Sent: Monday, March 01, 2004 12:43 PM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Re: Question about FREQOUT
    >
    >
    > My question pertains to BS2 which comes with BOE BOT.
    >
    > The BOE BOT manual uses higher frequency than what is supposed to
    be
    > the limit according to the BS manual for BS2.
    >
    > Where is the harmonics coming from?
    >
    > Thanks.
    >
    >
    >
    > --- In basicstamps@yahoogroups.com, Bruce Bates <bvbates@u...>
    wrote:
    > > At 06:12 PM 3/1/04 +0000, basicstampede wrote:
    > > >My BOE-BOT manual uses statement such as
    > > >
    > > >FREQOUT 0, 1, 41000, but according to the manual, highest
    > frequency
    > > >is 32767.
    > > >
    > > >They seem to contradict each other.
    > >
    > > The 32767 restriction is for the BS-2 and BS-2e. Other Stamps are
    > capable of higher frequencies per the table in the PBASIC Stamp
    > Manual.
    > >
    > >
    > > >What is the real limit on frequency?
    > > >
    > > >What is the side effect of a frequency higher than 32767?
    > Anything?
    > > >
    > > >Thank you.
    > > >
    > > >
    > > >Bruce Bates
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the
    Subject
    > and Body of the message will be ignored.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
    >
    >
    > This message has been scanned by WebShield. Please report SPAM to
    > abuse@p...
  • ArchiverArchiver Posts: 46,084
    edited 2004-03-01 23:04
    PBASIC does not do range checking so if you try to put a 16-bit value
    into a 4-bit variable, what you'll end up with is the lower 4-bits.
    That's what happens here, you're getting the lower 15 bits and a
    harmonic of the resultant frequency is what is modulating the IR diode.

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: basicstampede [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=hBuThDhDsB7hroekllvgSdvh9hJqMWnWQ4yhXbAGcFtjBhUjxbGvWvnygBCmHqfSZITgPayKgnpOqh4paZxtQpHM]basicstampede@y...[/url
    Sent: Monday, March 01, 2004 1:03 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Question about FREQOUT


    I'm confused. If you say that the upper limit is 32767, then how
    does the statement FREQOUT 1, 1, 41000 even compile? Or does it
    actually do FREQOUT 1, 1, 32767 instead?

    Thanks.

    --- In basicstamps@yahoogroups.com, "Jon Williams" <jwilliams@p...>
    wrote:
    > The output from FREQOUT is actually a string of variable-width
    square
    > waves. If you filter the output you'll get a nice sine wave at the
    > targe frequency. Mathematically, a square wave is composed of its
    root
    > frequency and all odd harmonics. It turns out that when you tell
    the
    > Stamp to FREQOUT at 38500 (modulation for an IR LED) that the
    harmonics
    > generated are strong enough at that frequency to do the job.
    >
    > One of our staff engineers, Andy, has taken this even further and
    done
    > some really neat frequency sweeping to do distance measuring with a
    > BOE-Bot. Download the Robotics text for that.
    >
    > And, contrary to other posts, the upper end of FREQOUT is indeed
    32767
    > -- for all BASIC Stamps.
    >
    > -- Jon Williams
    > -- Applications Engineer, Parallax
    > -- Dallas Office
    >
    >
    >
    Original Message
    > From: basicstampede [noparse][[/noparse]mailto:basicstampede@y...]
    > Sent: Monday, March 01, 2004 12:43 PM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Re: Question about FREQOUT
    >
    >
    > My question pertains to BS2 which comes with BOE BOT.
    >
    > The BOE BOT manual uses higher frequency than what is supposed to
    be
    > the limit according to the BS manual for BS2.
    >
    > Where is the harmonics coming from?
    >
    > Thanks.
    >
    >
    >
    > --- In basicstamps@yahoogroups.com, Bruce Bates <bvbates@u...>
    wrote:
    > > At 06:12 PM 3/1/04 +0000, basicstampede wrote:
    > > >My BOE-BOT manual uses statement such as
    > > >
    > > >FREQOUT 0, 1, 41000, but according to the manual, highest
    > frequency
    > > >is 32767.
    > > >
    > > >They seem to contradict each other.
    > >
    > > The 32767 restriction is for the BS-2 and BS-2e. Other Stamps are
    > capable of higher frequencies per the table in the PBASIC Stamp
    > Manual.
    > >
    > >
    > > >What is the real limit on frequency?
    > > >
    > > >What is the side effect of a frequency higher than 32767?
    > Anything?
    > > >
    > > >Thank you.
    > > >
    > > >
    > > >Bruce Bates
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