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About FSK Modulation at HMC703-EVB

The customer wants to know how to use HMC Eval Software.

He is tring FSK modulation at HMC-EVB of HMC703LP4E.

He wants to control FSK modulation by the external triger.

<Condition>

F0 : 1.509375GHz (=24.15GHz/16)

F1 : 1.50984375GHz (=24.1575GHz/16)

Frequency change timing : F0/50us, F1/50us, F0/50us, F1/50us, .......

He does not know how to use HMC Software.

If you have H703-EVB manual or know how to use FSK modulation at H703-EVB, please provide/tell me.

He is using HMC703 Eval board and HMC-Software.

BR, Tomo

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  • For this application some modifications are required on the HMC703 eval board.  The board comes with a HMC508 VCO which is limited to 7G output. Another VCO is required, something like the HMC739 will do the job.  This particular VCO provides a divide-by 16 output which can be connected to the HMC703 RF input at J1.

    1. Disable the HMC508 by removing J7
    2. Remove R4 to prevent a stub on Vtune
    3. Remove R2 to prevent a stub on RF input
    4. Disable the power splitter by installing zero ohm resistor R3
    5. Install dc block capacitor at R1.  This is necessary to prevent loading the HMC739 output.
    6. Change the attenuator value to 3dB -- remove R16 and R8, change R15 and R7 to 300 ohms, change R12 to 20 ohms
    7. Enable the Vtune output by installing zero ohm resistor R9
    8. Connect the VCO output to J1 and the VCO Vtune input to J4

    I've attached a register programming file you can use to initialize the HMC703 registers for FM operation with external trigger.  This will configure the device to toggle between 24.15GHz and 24.1575GHz depending on the trigger level.  Use the eval board software to load this register file (click "load Reg File").   Once configured the output should lock to 24.15G when trigger is low.

    hmc703_w_hmc739_frac_fm.txt.zip
Reply
  • For this application some modifications are required on the HMC703 eval board.  The board comes with a HMC508 VCO which is limited to 7G output. Another VCO is required, something like the HMC739 will do the job.  This particular VCO provides a divide-by 16 output which can be connected to the HMC703 RF input at J1.

    1. Disable the HMC508 by removing J7
    2. Remove R4 to prevent a stub on Vtune
    3. Remove R2 to prevent a stub on RF input
    4. Disable the power splitter by installing zero ohm resistor R3
    5. Install dc block capacitor at R1.  This is necessary to prevent loading the HMC739 output.
    6. Change the attenuator value to 3dB -- remove R16 and R8, change R15 and R7 to 300 ohms, change R12 to 20 ohms
    7. Enable the Vtune output by installing zero ohm resistor R9
    8. Connect the VCO output to J1 and the VCO Vtune input to J4

    I've attached a register programming file you can use to initialize the HMC703 registers for FM operation with external trigger.  This will configure the device to toggle between 24.15GHz and 24.1575GHz depending on the trigger level.  Use the eval board software to load this register file (click "load Reg File").   Once configured the output should lock to 24.15G when trigger is low.

    hmc703_w_hmc739_frac_fm.txt.zip
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