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Topics - FaberAST

Pages: 1 [2] 3 4
16
SignalScope Pro / Welcome to the SignalScope Pro forum
« on: June 09, 2009, 06:16:26 AM »
SignalScope Pro turns an iPhone or iPod touch into a powerful audio, electronics, and vibration analyzer. Significant new features include a 1/3-octave real-time spectrum analyzer (RTA), acoustic and vibration measurements, a built-in signal generator, and the ability to save and download measurement data.

Feel free to use this forum to post your questions, suggestions, tips, tricks, and experiences regarding SignalScope Pro on iPhone.

Thank you!

17
SignalScope / MOVED: Polarity Check with Pulses
« on: April 13, 2009, 09:12:19 PM »

19
SoundMeter / Welcome to the SoundMeter forum!
« on: August 11, 2008, 09:22:20 PM »
A sound level meter app for iPhone has been a hugely popular request. Now that SoundMeter is available, you can voice your questions, concerns, praises, and suggestions in this forum.

20
SignalSuite / How good is the iPhone's audio?
« on: July 12, 2008, 03:09:52 PM »
Check out the new post in Articles for some insight into this question.


21
SignalScope / How good is the iPhone's audio?
« on: July 12, 2008, 03:08:13 PM »
Check out the new post in Articles for some insight into this question.


22
Articles / How good is the iPhone's audio?
« on: July 12, 2008, 03:05:54 PM »
The question has been raised, particularly in light of an article that suggested that the iPhone's audio hardware was inadequate to use in testing audio systems.

Below are plots of measurements made of the (original) iPhone. These are direct measurements (not post-processed recordings) made of the iPhone with Electroacoustics Toolbox and an Edirol FA-101 interface, using SignalScope's play through feature (on iPhone). The sample rate of the iPhone and the Edirol interface was set to 48 kHz. These measurements include the response of the iPhone's input and output hardware (via the headset connector). Neither the output nor the input hardware, by itself, should be any worse than any of these measurements.

The large amount of delay is due to the fact that the signal is getting buffered inside the iPhone as it gets passed from the input to the output. (For what it's worth, lower audio throughput latency is possible with the iPhone, but at the expense of higher CPU load).

The square wave plot is a direct capture of two square waves being generated simultaneously by SignalSuite on the iPhone.

Here are the plots:


Figure 1. Impulse response.



Figure 2. Frequency Response Magnitude.



Figure 3. Frequency Response Phase. The phase drops off rapidly because of the large latency of the measured iPhone setup.



Figure 4. Group Delay. The delay is nearly constant with respect to frequency.



Figure 5. Signal to Noise Ratio.



Figure 6. Coherence. The coherence was measured simultaneously with all the other measurements, above, and indicates that the measurements are all valid. (A coherence of exactly 1 would result from measuring a perfectly linear, time-invariant, noise free device.)



Figure 6. 1 kHz and 100 Hz square waves. These square waves were produced simultaneously on the two headphone channels by SignalSuite, running on the iPhone.


Additional efforts to quantify the response of the iPhone's audio hardware are underway...

23
Some customers have reported the following error message when trying to download SignalSuite, after paying for it:

"Unable to check for purchases. An unknown error occurred (-206)."

The problem needs to be resolved by iTunes support. If this has happened to you, I'm afraid the best thing you can do is submit a detailed report to iTunes (instructions, here), and wait until the problem is fixed (hopefully, within a day or two). Judging by the discussion boards at Apple's support site, similar problems have occurred recently with other iTunes downloads (like TV shows), and they appear to have been resolved.

We're doing all we can to get the right message to the right people as soon as possible to get this problem solved.

If you have successfully downloaded SignalSuite, please tell us about it.

Thank you for your patience and for your support.

Ben


UPDATE:  Sometime on Monday afternoon, July 14, SignalScope and SignalSuite downloads began to work. Thanks for your patience, everyone!

24
Some customers have reported the following error message when trying to download SignalScope, after paying for it:

"Unable to check for purchases. An unknown error occurred (-206)."

The problem needs to be resolved by iTunes support. If this has happened to you, I'm afraid the best thing you can do is submit a detailed report to iTunes (instructions, here), and wait until the problem is fixed (hopefully, within a day or two). Judging by the discussion boards at Apple's support site, similar problems have occurred recently with other iTunes downloads (like TV shows), and they appear to have been resolved.

We're doing all we can to get the right message to the right people as soon as possible to get this problem solved.

If you have successfully downloaded SignalScope, please tell us about it.

Thank you for your patience and for your support.

Ben Faber

UPDATE:  Sometime on Monday afternoon, July 14, SignalScope and SignalSuite downloads began to work. Thanks for your patience, everyone!


25
SignalSuite / Welcome to the SignalSuite for iPhone/iPod touch forum!
« on: July 11, 2008, 11:21:02 AM »
The mobile version of SignalSuite debuted in the iPhone App Store on opening day. SignalSuite adds precision signal generator capabilities to your iPhone or iPod touch.

Feel free to use this forum to post your questions, suggestions, tips, tricks, and experiences regarding SignalSuite on iPhone.

Thank you!

26
SignalScope / Getting signals into the iPhone [UPDATED June 9, 2009]
« on: July 11, 2008, 11:13:06 AM »
Update, June 9, 2009: The latest audio input/output information, for iPhone and iPod touch devices, is now available on the blog.

This topic addresses several questions that have been coming in regarding SignalScope on the iPhone.

There are basically four ways to get signals into SignalScope on iPhone:
  • Built-in Microphone. When using the built-in microphone, the sample rate is limited to 8 kHz, so you only get about a 4 kHz bandwidth.
    Update, July 29, 2008: The iPhone 3G can sample the built-in mic at 48 kHz, so the 8 kHz sample rate limitation only applies to first-generation iPhones.
  • Headset Microphone. With the headset mic, the sample rate will jump up to 48 kHz. I don't know how flat the mic response is, but even inexpensive electret microphones can exhibit a remarkably flat response. I have measured frequencies over 20 kHz in SignalScope with the iPhone's headset mic.
  • Headset Input. The headset input allows for a single channel of audio band data. If you want to use anything other than a headset mic, you'll need an adapter cable. A standard mini-plug (1/8-inch) to RCA A/V cable should work (that's a four-conductor mini-plug on one end and three RCA plugs on the other). The recessed jack on the original iPhone may require another adapter, or modification of the A/V cable. I haven't really nailed down the acceptable voltage range, although the input seems to be expecting a low-level mic signal, so input signals may need to be attenuated before they get to the iPhone. A Type 1 measurement microphone (50 mV/Pa), with a unity gain preamp, seemed to clip the iPhone input very easily (with relatively low sound levels).
  • Accelerometer. In SignalScope, the accelerometer is sampled at 100 Hz and currently supports units of "g" (that's gravity, not grams). I don't know how accurate the calibration is--it was calibrated by the manufacturer.

Notes:
  • SignalScope currently does not support (sensitivity) calibration of the audio input, or audio signal units other than %FS (percent of full-scale, or clipping, voltage)--SignalScope Pro does.

Ben

27
SignalScope / Overheard on ProSoundWeb.com forums...
« on: July 11, 2008, 10:56:26 AM »
"^#T(*&#_+$!@ awesome ! Okay, that does it. It's iPhone time for me. That broke the camels' back."

The forum topic?  "SignalScope on iPhone"

28
SignalScope / Welcome to the SignalScope iPhone forum!
« on: July 11, 2008, 10:55:03 AM »
The mobile version of SignalScope debuted in the iPhone App Store on opening day. SignalScope turns your iPhone into a powerful, real-time spectrum analyzer and oscilloscope.

Feel free to use this forum to post your questions, suggestions, tips, tricks, and experiences regarding SignalScope on iPhone.

Thank you!

29
Product Sales & Activation FAQ / Do you offer educational discounts?
« on: July 23, 2007, 11:16:27 AM »
Do you offer educational discounts?

Yes. Currently, discount pricing is offered to qualified education customers purchasing single (or multiple) licenses of SignalScope/Pro, SignalSuite, and Electroacoustics Toolbox. Please contact us for details.

30
SignalSuite FAQ / Can SignalSuite produce DC signals?
« on: July 23, 2007, 11:11:54 AM »
Can SignalSuite produce DC signals?

Currently, SignalSuite does not support DC signals, particularly because typical audio interfaces do not support DC either.  (If you are aware of an audio interface that does support DC, or would be interested in support for data acquisition hardware that produces DC output, please let us know.)

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