• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 8 subscribers
  • Views 1459 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

POWER METER IN GC5016

CarrierCHN
Prodigy 110 points

hello:

I use GC5016 in DDC mode with 4 channel. Instead of using cmd5016, chip configuration is done by a DSP chip at power up. Now i want to read the power meter. When  there is no signal input, i think the value should be of white noise and the value of four channel should be similar.But now the power meter value read from CHB/CHC is about lsb=12430,msb=2302, and the value read from CHA/CHD is about lsb=4506,msb=0. I exchange  the nco value between CHA(CHC) and CHB(D), and the power meter exchanges the same.

I confuse what leads to this result.  

  • 0
    TI__Mastermind 37500 points

    Hello,

    There is a user guide, sample configurations, and the cmd5016 tool on the TI website.  We don't recommend programming the GC5016 without the cmd5016 tool.

    There are two methods to program and update the power meter in section 13.8 of the datasheet.  Sometimes if the power meter is not properly programmed it contains a non-correct data that is stuck after initialization. 

    In 4 channel DDC mode, you can pick a decimation that has been previously tested, set the digital input to a specific port where you can input a DC level (special consideration for AC coupled ADC input, need to inject after transformer or caps).    Set the mixer to 0Hz, and select this channel.  With the mixer set to 0, for a real input the I value will contain the DC level.  You will have a DC gain associated with the CIC and PFIR.  When you set the power meter for integrating a number of samples, you can use a DC input and the mixer set to 0, or a tone input and the mixer set for the tone frequency.  You should be able to change the power meter setup, and you should get a predictable increase in the I^2+Q^2 summation by changing the integration counts.  The datasheet discusses two methods to synchronize reading the power meter.  If you integrate 256 samples or 512 samples, you should be able to calculate the integrated difference, and it should be within a few% at higher signal levels.  Note: The power meter integration, shown in Figure 11, shows that the top 9 of 20 bits are used, so there is a low signal cutoff. 

    Regards,

    Radio Joe

  • 0 in reply to Radio-Joe
    Prodigy 110 points

    Hello,

    What confused me is that  the configuration of 4 channel is same,but the result of power meter is different.   By the way, I read the power meter data asynchronously and didn't use either of two methods in datasheet .

    For example, channel A:

    1,set  page 0x13 address 0x1a,0x1b,0x1c,0x1d;

    2,set pwr_mtr_sync to the same value as fir_sync(page 0x14 address 0x15);

    3,write 0 to page 0x13 address 0x1c;

    4,write 0xFFFF to page 0x13 address 0x1d;

    5,read 0x1a and 0x1b twice( data1 , data2), if data1=data2, back to step 3 ; otherwise reread.

    CHB, CHC, CHD have the same operation. Is there something wrong?

    Regards,

    Jianwen Jiang