[Discuss-gnuradio] Re: Re: xcvr2450, v3.2 and usrp1

[William Sherman]

Eric Blossom wrote:
> On Mon, Jun 22, 2009 at 06:30:26AM +0200, William Sherman wrote:
>> The xcvr transmits at the incorrect frequency. I just looked at it with 
>> a wider span of the spectrum analyser. Asking it to transmit at 2.45GHz, 
>> it instead transmits signals at 2.58GHz. What could be causing this?
> 
> Not sure.
> 
> Try using:
> 
>   $ usrp_sigggen.py -f 2.45G --const -a 8000
> 
> Eric

No it still transmits at 2.58GHz.

I guess there's a problem with db_xcvr2450.cc?

Here is the db_xcvr2450.cc set_freq code in my gnuradio 3.2 
installation:

struct freq_result_t
xcvr2450::set_freq(double target_freq)
{
  struct freq_result_t args = {false, 0};

  double scaler;

  if(target_freq > 3e9) {
    d_five_gig = 1;
    d_ad9515_div = 3;
    scaler = 4.0/5.0;
  }
  else {
    d_five_gig = 0;
    d_ad9515_div = 3;
    scaler = 4.0/3.0;
  }

  if(target_freq > 5.408e9) {
    d_highband = 1;
  }
  else {
    d_highband = 0;
  }

  double vco_freq = target_freq*scaler;
  double sys_clk = usrp()->fpga_master_clock_freq();  // Usually 64e6
  double ref_clk = sys_clk / d_ad9515_div;

  double phdet_freq = ref_clk/d_ref_div;
  double div = vco_freq/phdet_freq;
  d_int_div = int(floor(div));
  d_frac_div = int((div-d_int_div)*65536.0);
  // double actual_freq = 
phdet_freq*(d_int_div+(d_frac_div/65536.0))/scaler;

  //printf("RF=%f VCO=%f R=%d PHD=%f DIV=%3.5f I=%3d F=%5d ACT=%f\n",
  //   target_freq, vco_freq, d_ref_div, phdet_freq,
  //   div, d_int_div, d_frac_div, actual_freq);

  set_gpio();
  set_reg_int_divider();
  set_reg_frac_divider();
  set_reg_bandselpll();

  args.ok = lock_detect();
#ifdef NO_LO_OFFSET
  args.baseband_freq = target_freq;
#else
  args.baseband_freq = actual_freq;
#endif

  if(!args.ok){
    printf("Fail %f\n", target_freq);
  }
  return args;
}
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