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Amplitude Modulation with input carrier frequency of 10KHz

Mala Madanagopala
Prodigy 50 points
Other Parts Discussed in Thread: LMH6503, VFC32

Dear all,

Could any one suggest if there is any IC available for Amplitude Modulation with input carrier frequency of 10KHz? or please suggest some circuitry which can operate fine at all motor speeds. I am thinking of adding amplitude and frequency modulator and demodulator circuits to be added to inject hardware faults interface between ECU and Resolver. So amplitude and frequency of any of all the lines of excitation, sine or cosine has to be changed without affecting other lines. could any one suggest some interface circuitry?

Regards,

Mala

  • 0
    TI__Genius 13935 points

    Hello Mala,

    What format is your baseband data?  It may be that a DAC would be your best bet.  If you signals are all analog then maybe a mixer would be worth trying.  Otherwise you could look at the LMH6503/2/4, they are voltage controlled variable gain amplifiers.

    Regards,

    Loren

  • 0 in reply to Loren Siebert 1
    Prodigy 50 points

    Dear Loren,

    Signals out of controller board are Excitation+ and Excitation-(modulation signal) and out of resolver are Sin+, Sin-, Cos+, Cos-(Modulated signal). they are all analog. to introduce fault when the motor is rotating, need to vary amplitude on any one of the lines and also frequency on any one of the lines.

    your answer did help me. could you please suggest me more on this. as all signals are of 10KHz level, may not be able to use communication related chips.

    Thank you.

  • 0 in reply to Mala Madanagopala
    TI__Genius 13935 points

    Hello Mala,

    At lower frequencies the mixing function is often called an analog multiplier.  I do not know if TI has any chips of this kind, but I did a google search and found some that may be what your are looking for. 


    If you need to vary frequency that is a frequency modulator or a voltage to frequency converter.  Here is an app note on a TI part that does this function.  http://www.ti.com/lit/ds/symlink/vfc32.pdf  Often a PLL can be used as well, or just a varactor tuned oscillator, depending on your needs. 

    I know that motor control is a big part of TI business, but it is mostly handled in other groups.  If you enter Motor Control into the forum search bar you will get some related results where people have implemented similar solutions.

    Most of the parts used in motor control are not high speed, so they would fall in the precision category. 

    Even with analog control signals, it may be easier to digitize them with one of our microprocessors and then implement the control in software.  There appear to be several threads covering these issues in the forum, however I am not expert in motor control so I don't know how thoroughly this topic is covered.

    http://e2e.ti.com/support/microcontrollers/c2000/f/171/t/230180.aspx

    Regards,

    Loren