What is meant by 'local' in local oscillator?












1












$begingroup$


We know that a local oscillator (LO) is an electronic oscillator used with a mixer to change the frequency of a signal.




  • But what do we mean by 'local'?

  • How is 'local oscillator' different from normal oscillator?

  • Why a
    normal oscillator like LC-tank circuit or an opamp circuit can't be used in
    heterodyne receiver?










share|improve this question











$endgroup$








  • 2




    $begingroup$
    The local oscillator is the one "local to", i.e., part of, your radio--as opposed to the remote oscillator used by the transmitter.
    $endgroup$
    – Hearth
    54 mins ago
















1












$begingroup$


We know that a local oscillator (LO) is an electronic oscillator used with a mixer to change the frequency of a signal.




  • But what do we mean by 'local'?

  • How is 'local oscillator' different from normal oscillator?

  • Why a
    normal oscillator like LC-tank circuit or an opamp circuit can't be used in
    heterodyne receiver?










share|improve this question











$endgroup$








  • 2




    $begingroup$
    The local oscillator is the one "local to", i.e., part of, your radio--as opposed to the remote oscillator used by the transmitter.
    $endgroup$
    – Hearth
    54 mins ago














1












1








1





$begingroup$


We know that a local oscillator (LO) is an electronic oscillator used with a mixer to change the frequency of a signal.




  • But what do we mean by 'local'?

  • How is 'local oscillator' different from normal oscillator?

  • Why a
    normal oscillator like LC-tank circuit or an opamp circuit can't be used in
    heterodyne receiver?










share|improve this question











$endgroup$




We know that a local oscillator (LO) is an electronic oscillator used with a mixer to change the frequency of a signal.




  • But what do we mean by 'local'?

  • How is 'local oscillator' different from normal oscillator?

  • Why a
    normal oscillator like LC-tank circuit or an opamp circuit can't be used in
    heterodyne receiver?







oscillator terminology






share|improve this question















share|improve this question













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edited 47 mins ago







Shadow

















asked 59 mins ago









ShadowShadow

170312




170312








  • 2




    $begingroup$
    The local oscillator is the one "local to", i.e., part of, your radio--as opposed to the remote oscillator used by the transmitter.
    $endgroup$
    – Hearth
    54 mins ago














  • 2




    $begingroup$
    The local oscillator is the one "local to", i.e., part of, your radio--as opposed to the remote oscillator used by the transmitter.
    $endgroup$
    – Hearth
    54 mins ago








2




2




$begingroup$
The local oscillator is the one "local to", i.e., part of, your radio--as opposed to the remote oscillator used by the transmitter.
$endgroup$
– Hearth
54 mins ago




$begingroup$
The local oscillator is the one "local to", i.e., part of, your radio--as opposed to the remote oscillator used by the transmitter.
$endgroup$
– Hearth
54 mins ago










3 Answers
3






active

oldest

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8












$begingroup$

You got that wrong:
The "local" in oscillator doesn't describe the kind of oscillator used. It could just be an LC-tank, it could be a crystal-derived oscillator, it could be something synthesized from a reference clock or something recovered from the data stream received:



The "local" in oscillator refers to the fact that it's what the mixer uses locally to mix down or up, as opposed to the oscillator at the other end of the communication, which simply isn't the same oscillator.






share|improve this answer









$endgroup$





















    5












    $begingroup$

    Think of frequencies. The local oscillator generates a local frequency, that is only used by your mixer as the intermediate frequency. Whereas the transmitter frequency is not staying on your local board but flying through the air as radio waves. The transmitter and the receiver does not need to use the same intermediate frequency, but could use different local oscillators.






    share|improve this answer









    $endgroup$





















      1












      $begingroup$

      LO to an RF Engineer means a sine signal "local" or "within the device" used for heterodyning or mixing.






      share|improve this answer









      $endgroup$













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        3 Answers
        3






        active

        oldest

        votes








        3 Answers
        3






        active

        oldest

        votes









        active

        oldest

        votes






        active

        oldest

        votes









        8












        $begingroup$

        You got that wrong:
        The "local" in oscillator doesn't describe the kind of oscillator used. It could just be an LC-tank, it could be a crystal-derived oscillator, it could be something synthesized from a reference clock or something recovered from the data stream received:



        The "local" in oscillator refers to the fact that it's what the mixer uses locally to mix down or up, as opposed to the oscillator at the other end of the communication, which simply isn't the same oscillator.






        share|improve this answer









        $endgroup$


















          8












          $begingroup$

          You got that wrong:
          The "local" in oscillator doesn't describe the kind of oscillator used. It could just be an LC-tank, it could be a crystal-derived oscillator, it could be something synthesized from a reference clock or something recovered from the data stream received:



          The "local" in oscillator refers to the fact that it's what the mixer uses locally to mix down or up, as opposed to the oscillator at the other end of the communication, which simply isn't the same oscillator.






          share|improve this answer









          $endgroup$
















            8












            8








            8





            $begingroup$

            You got that wrong:
            The "local" in oscillator doesn't describe the kind of oscillator used. It could just be an LC-tank, it could be a crystal-derived oscillator, it could be something synthesized from a reference clock or something recovered from the data stream received:



            The "local" in oscillator refers to the fact that it's what the mixer uses locally to mix down or up, as opposed to the oscillator at the other end of the communication, which simply isn't the same oscillator.






            share|improve this answer









            $endgroup$



            You got that wrong:
            The "local" in oscillator doesn't describe the kind of oscillator used. It could just be an LC-tank, it could be a crystal-derived oscillator, it could be something synthesized from a reference clock or something recovered from the data stream received:



            The "local" in oscillator refers to the fact that it's what the mixer uses locally to mix down or up, as opposed to the oscillator at the other end of the communication, which simply isn't the same oscillator.







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered 52 mins ago









            Marcus MüllerMarcus Müller

            32.5k35894




            32.5k35894

























                5












                $begingroup$

                Think of frequencies. The local oscillator generates a local frequency, that is only used by your mixer as the intermediate frequency. Whereas the transmitter frequency is not staying on your local board but flying through the air as radio waves. The transmitter and the receiver does not need to use the same intermediate frequency, but could use different local oscillators.






                share|improve this answer









                $endgroup$


















                  5












                  $begingroup$

                  Think of frequencies. The local oscillator generates a local frequency, that is only used by your mixer as the intermediate frequency. Whereas the transmitter frequency is not staying on your local board but flying through the air as radio waves. The transmitter and the receiver does not need to use the same intermediate frequency, but could use different local oscillators.






                  share|improve this answer









                  $endgroup$
















                    5












                    5








                    5





                    $begingroup$

                    Think of frequencies. The local oscillator generates a local frequency, that is only used by your mixer as the intermediate frequency. Whereas the transmitter frequency is not staying on your local board but flying through the air as radio waves. The transmitter and the receiver does not need to use the same intermediate frequency, but could use different local oscillators.






                    share|improve this answer









                    $endgroup$



                    Think of frequencies. The local oscillator generates a local frequency, that is only used by your mixer as the intermediate frequency. Whereas the transmitter frequency is not staying on your local board but flying through the air as radio waves. The transmitter and the receiver does not need to use the same intermediate frequency, but could use different local oscillators.







                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered 52 mins ago









                    LundinLundin

                    3,8211131




                    3,8211131























                        1












                        $begingroup$

                        LO to an RF Engineer means a sine signal "local" or "within the device" used for heterodyning or mixing.






                        share|improve this answer









                        $endgroup$


















                          1












                          $begingroup$

                          LO to an RF Engineer means a sine signal "local" or "within the device" used for heterodyning or mixing.






                          share|improve this answer









                          $endgroup$
















                            1












                            1








                            1





                            $begingroup$

                            LO to an RF Engineer means a sine signal "local" or "within the device" used for heterodyning or mixing.






                            share|improve this answer









                            $endgroup$



                            LO to an RF Engineer means a sine signal "local" or "within the device" used for heterodyning or mixing.







                            share|improve this answer












                            share|improve this answer



                            share|improve this answer










                            answered 23 mins ago









                            Sunnyskyguy EE75Sunnyskyguy EE75

                            64.2k22294




                            64.2k22294






























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