Loading ...
Sorry, an error occurred while loading the content.

Re: Noise band around the centre frequency

Expand Messages
  • neil whiting
    Hi Rob, I too had problems with feedback from input to output using a SB Live 24 PCI card. I worked round it by using the onboard AC97 sound for output, rather
    Message 1 of 3 , May 31, 2006
    • 0 Attachment
      Hi Rob,

      I too had problems with feedback from input to output using a SB Live
      24 PCI card. I worked round it by using the onboard AC97 sound for
      output, rather than by finding a proper fix :-)

      73, Neil G4BRK

      --- In softrock40@yahoogroups.com, "Rob Campbell" <gm6oqn@...> wrote:
      >
      > Hi,
      >
      > I've seen a few comments about the noise around the centre frequency
      > and would like to add my experiences.
      >
      > While I was testing my SR6 at work I had the output connected to the
      > audio-in socket on the back of my keyboard and a pair of small
      > headphones on the audio-out. In other words, the I/Q signals from
      > the SR and the PC audio out were bundled together in the keyboard
      > cable (odd but useful HP arrangement). I could see the usual spike
      > at the centre frequency but with no input signal from the rf signal
      > generator, when I increased the volume on the headphones (they've
      > got their own in-line control) the noise band also increased!
      > I can't see any reason for this other than crosstalk between the I/Q
      > and audio-out signals. To put it another way, careful screening and
      > routing of the audio signals should minimise crosstalk and help keep
      > the noise band to a low level.
      >
      > I wonder if this is why some sound cards behave better than others
      > in this respect - manufacturers paying close attention to signal
      > routing to keep crosstalk down.
      >
      > Rob GM6OQN
      >
    Your message has been successfully submitted and would be delivered to recipients shortly.