Return to KLUBNL.PL main page
| To: | [email protected] |
|---|---|
| Subject: | Re: LF: WOLF Monkey Business |
| From: | Markus Vester <[email protected]> |
| Date: | Tue, 31 Jan 2012 03:05:31 -0500 (EST) |
| Dkim-signature: | v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20110426; t=1327997132; bh=isNSjlUxT5yXQb/N1F8Hm11eRjm7J+t7/F3BL/X3szk=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=Gz/K8i7yOU4glfunczzg+cW7ysq+UkpB9GzNG5d2ciTgcyCxy58Gp7hK/9O+Ckhn3 n5GShKqkVbVfV8uz+QLAJEJiNBkI+Vju5waoU3VN0ZZeGcg2U2F1n/LSEgiCaATp1Q tlVMeIzKsts42QoAE926CKTjpOUPtJU9OYTjMvrI= |
| In-reply-to: | <[email protected]> |
| References: | <[email protected]><EB550E30D4E84FCEBDEACF07F9E2A7A4@White><CAK59VFOT_JoAbOjxGxdz3NB4XWRodyN54=EgutPgb9YowueA9Q@mail.gmail.com><50DDDC5E26754BC284D529DCB4A1C2C3@White><[email protected]><[email protected]><[email protected]><[email protected]><[email protected]><[email protected]><[email protected]><[email protected]> <[email protected]> |
| Reply-to: | [email protected] |
| Sender: | [email protected] |
|
Bill, thanks for the hint! A couple of days ago, I stumbled across this problem but didn't get to the bottom of it. I had attempted to evade a slight difference between the netbook's input and output samplerate at nominal 11.025. I tried 48000, 24000 and 8000 in WolfGui, and each time the output audio was low pitched. I ended up properly calibrating input and output SR separately, entered the results (11025.387 and 11024.770 in my case) into the config, and all was ok.
Best 73,
Markus
-----Ursprüngliche Mitteilung----- Von: Bill de Carle <[email protected]> An: rsgb_lf_group <[email protected]> Verschickt: Di, 31 Jan 2012 3:44 am Betreff: LF: WOLF Monkey Business I have here two versions of the original WOLF command-line program:
0.51 and 0.61 - apparently there is also a version 0.62 which is used by the GUI program. I wanted to duplicate what Stefan did using the GUI version: generate a signal on 8970 Hz using 24000 s/s. It *seemed* to work OK but when I examined the sound card output signal with Cool Edit, the frequency was way low - about 8241 Hz instead of 8970. So I went back to the original command line programs. I found that versions 0.51 and 0.61 apparently worked, generating 2,304,000 audio samples (exactly 96 seconds at 24000 s/s) to a file called WOLFX.WAV. Unfortunately the samplerate in the .wav file header was coded as 8000 s/s, which means if we played it back it would run for 288 seconds and the audio carrier frequency would appear at 2990 Hz. So I went in and manually changed the s/s field in the wav header to 24000 s/s. Then the file worked OK. I was able to decode the message by mixing the 8970 Hz down to 800 Hz and decimating the sample rate to 8000 s/s. Turning again to the GUI version, I asked it to encode a .wav file at 24000 s/s with a carrier freq of 8970 Hz. It reported version 0.62 and everything OK. However, when I examined the WOLFX.WAV file so created, its .wav header said the samplerate was 22050 s/s instead of 24000 s/s! That explains why the real-time GUI uutput seemed low in frequency: 8970 * 22050 / 24000 = 8241.1875 Hz. The upshot is we need to manually check the wav header and set the s/s field to 24000 instead of whatever else it might say. And furthermore, don't trust the real-time Tx soundcard output signal frequency with the GUI version, especially when using odd-ball sample rates and high output frequencies which may never have been tested. Be aware that WOLF generates envelope-shaped audio, so it might be more difficult to convert it to a clean square wave to drive a Tx, especially near the phase transitions where the amplitude drops down to zero. 73, Bill VE2IQ |
| <Prev in Thread] | Current Thread | [Next in Thread> |
|---|---|---|
| ||
| Previous by Date: | LF: WOLF Monkey Business, Bill de Carle |
|---|---|
| Next by Date: | LF: Opera again, mal hamilton |
| Previous by Thread: | LF: WOLF Monkey Business, Bill de Carle |
| Next by Thread: | Re: LF: WOLF Monkey Business, Stefan Schäfer |
| Indexes: | [Date] [Thread] [Top] [All Lists] |