Legacy Technotes & Appnotes
These Technotes and Appnotes are written for legacy AP instruments and we no longer support them. They are hosted here for the convenience of our customers. Click here for current Technotes and Appnotes.
Legacy Technotes | Legacy Appnotes
| Technote 103 Dolby Digital Testing using the Audio Precision 2700 Series This Technote describes a set of over 30 AP Basic macros created to make it easier to take measurements required for Dolby Digital Certification. |
TN-103.pdf (490 kB) All Files (780 kB) |
| Technote 102: Testing Personal Media players using QuickTest This Technote describes the ATS and AP2700 Series QuickTest application. QuickTest allows users to run comprehensive tests for personal media players quickly and easily. QuickTest measures DC offset, output level, distortion, frequency response, phase deviation, noise and crosstalk, and compares the results to defined pass / fail limits. These results, with identifying information, are displayed on-screen and saved in a file for post-test review. |
TN-102.pdf (483 kB) All files (8.6 MB) |
| Technote 101: LabVIEW ActiveX Automation for Audio Precision instruments Basic principles and techniques needed to control an Audio Precision instrument using the control software (AP2700, ATS or APWIN) as an ActiveX automation server from within the NI LabView environment. |
TN-101.pdf (1.3 MB) All files (1.2 MB) |
| Technote 30: .WAV file Import This APWIN utility allows you to load any .wav files compatible with the Microsoft RIFF file format into APWIN and analyze them in the frequency or time domain. |
TN-30.pdf (310 kB) All files (398 kB) |
| Technote 29: Computing Group Delay This macro, entitled Group delay.apb, will compute and display the relative input-output time delay of a device as a function of frequency. |
TN-29.pdf (310 kB) All files (398 kB) |
| Technote 28: Measurement Microphone dB SPL Calibration Utility to set measurement microphone reference level so dBr = dBspl. |
TN-28.pdf (161 kB) All files (176 kB) |
| Technote 27: Polarity test Utility to test polarity between analog generator outputs and analog analyzer inputs. |
TN-27.pdf (66 kB) All files (100 kB) |
| Technotes 23 - 26 were republished together as Measurement Techniques for Digital Audio. | |
| Technote 22 was republished as Technote 101. | |
| Technote 21: Obtaining Frequency Response Measurements Using an Audio Program as the Test Signal This Technote describes the measurement of frequency response with System Two's dual-channel FFT using power spectrum averaging, which allows wide-band program material, such as music, to be used as the test signal. |
TN-21.pdf (213 kB) |
| Technote 20: Return Loss Measurements This Technote gives an overview of the concept of return loss in telephony. Return loss is an expression of the impedance mismatch in a transmission circuit which can give rise to reflection of signal energy. Sample hybrid circuits and their use in return loss measurements using Audio Precision instruments are described. |
TN-20.pdf (195 kB) |
| Technote 19: Create an HTML-Based Help System for AP Basic Macros This Technote is a short primer in using AP Basic to create and use the webBrowser ActiveX object to create a sophisticated HTML-based help system to guide production technicians through AP Basic macros. |
TN-19.pdf (263 kB) |
| Technote 18: Multitone Waveform Creation Utility for Use with FASTTEST This Technotebes the Makewave utility, an AP Basic procedure that simplifies the process of creating multitone waveform files to use with the analog and digital generators in System One and System Two instruments. |
TN-18.pdf (145 kB) All files (160 kB) |
| Technote 17: Computing THD Measurements from FFT Data Using THD.exe Conventional analog total harmonic distortion tests are made with a notch filter that removes the fundamental and makes a root sum square summation of all of the harmonics. FFT techniques, on the other hand, provide the absolute amplitude of each individual harmonic. This program will extract the necessary harmonic data and the fundamental amplitude, compute the rss summation and express the result as a conventional THD ratiometric value. |
TN-17.pdf (309 kB) All files (150 kB) |
Technote 16 is no longer available |
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| Technote 15: GPIB Communication from AP Basic This Technote describes how to setup communication between AP Basic and GPIB instrumentation (using the National Instruments GPIB Interface). |
TN-15.pdf (3.5 MB) All files (744 kB) |
| Technote 14: Testing Reduced Bit-Rate Codecs Using the System One DSP Program CODEC.dsp Reduced bit rate codecs cannot be properly tested using conventional sine wave test signals. Using multitone test signals and FFT analysis, the codec can be stressed to properly characterize how it will perform with program material. CODEC.dsp uses multitone testing techniques and internal automatic masking curve generation to facilitate objective and repeatable evaluation of codecs. |
TN-14.pdf (2.1 MB) All files (1.2 MB) |
| Technote 13: PC Sound Card Testing Using DSP-RIFF.exe Waveform Conversion Utility The multimedia expansion in the PC industry has created the need to test the audio performance of sound cards. This is a classic dual-domain application requiring testing of the D-to-A and A-to-D sections. This utility will translate either direction between the Microsoft RIFF .WAV file format and the Audio Precision DSP.WAV file format. This allows a System One test signal created by MAKEWAVE to be played back though the D-to-A, and a captured PC .WAV file to be analyzed on System One. |
TN-13.pdf (1.3 MB) All files (788 kB) |
| Technote 12: Creating Arbitrary Waveforms Using Time Record data System One DSP can produce signals based on a stored waveform loaded into its memory. A file with a .wav extension is downloaded to the DSP memory in System One to create the output. A utility called MAKEWAVE.exe is supplied With System One DSP that will convert an ASCII file that contains a time record into the .WAV format for use with the DSP generator. This Technote describes the format of the .waa ASCII files and how to create arbitrary waveforms. It assumes some programming knowledge. |
TN-12.pdf (167 kB) All files (100 kB) |
| Technote 11: Remote Test Data Retrieval: Send a FAX This Technote describes how to set up the PC that controls System One to be able to automatically send a fax to a designated fax machine with the results, in both tabular and graphical form, of the measured data. The measuring PC can be at a remote unattended location as the fax capability can be configured to operate completely automatically on time, event of data out-of-limits conditions. The description shows how to integrate commercial fax modem cards and software. |
TN-11.pdf (740 kB) |
| Technote 10: SWR-122 Series Switchers APIB Interface Description System One SWR series switchers are normally controlled via the APIB interface and S1.exe software. This Technote describes the APIB interface used on the switchers and explains how to control them from a generalized parallel port. A sample BASIC program is included to program the switchers from a PC parallel printer port. This Technote assumes programming and hardware knowledge. |
TN-10.pdf (167 kB) All files (140 kB) |
| Technote 9: Restructuring Multitrack Data Using MTRACKFR.exe Frequency response measurements on a Multitrack tape recorder are best made by successively measuring each track at the first frequency, then step to the second frequency and measure all tracks, and so on until all frequencies are measured. This produces a nested sweep file that plots amplitude versus track rather that amplitude versus frequency. This Technote contains a program that will restructure such data into the preferred format |
TN-9.pdf (171 kB) All files (135 kB) |
| Technote 8: Programmers' Reference to S1.exe DSP Waveform File Format System One DSP programs allow a SAVE WAVEFORM operation to store the time record data to disk. This Technote describes the internal structure of the *.wav files so produced. This would allow a knowledgeable programmer to extract data from this file for external post processing. It assumes intermediate programming expertise. |
TN-8.pdf (131 kB) |
| Technote 7: Programmers' Reference to S1.exe internal *.tst file format S1.exe *.tst files save instrument setups and test data in a binary format for space and speed efficiency. It is possible to examine such a file (or *.lim, *.eq, *.swp and *.ovl files) to extract this data. This Technote explains the internal structure of these files. It assumes intermediate programmers knowledge and is intended as a reference source, not a step-by-step explanation. |
TN-7.pdf (139 kB) |
| Technote 6: Computing Statistical Data From Nested Sweeps Using NSWEEP.exe When several plots of a parameter are acquired, it is often useful to reduce the large volume of data to statistical summaries such as maximum, minimum, average or delta. This Technote includes a program that will operate on an S1.exe nested sweep file to produce the statistical data mentioned above. The program can be run in an S1.exe DOS shell. |
TN-6.pdf (146 kB) All files (120 kB) |
| Technote 5: Usage Instructions for COMBINEC.EXE System One produces data files that are two or three columns wide with as many rows as measurement steps. Usually the first column is the source data and columns two and three are measured data. There are some applications where it is desirable to use some data from one file with data from another file to produce a third file. This Technote includes a C program that allows columnar data to be exchanged, moved or combined to produce a new data file. |
TN-5.pdf (159 kB) All files (110 kB) |
| Technote 4: Computing Equalization Curves Using EQCURVE.EXE Tests of recorded or transmission media often require an equalized generator signal. Modifying the response of a swept generator to reciprocate the pre-emphasis or de-emphasis characteristics of the device under test will prevent overload and yield a flat response at the output. This Technote includes a BASIC program that will compute a data file based on user supplied time constants. The data file can then be used as an S1.exe EQ curve. |
TN-4.pdf (133 kB) All files (111 kB) |
| Technote 3: Remote Site Data Retrieval of Test Results Using Modems Some measurement situations place the measurement equipment at some distance from the operator. Many broadcast applications require that System One be located at a distant, possibly unattended site. This Technote describes how to set up a modem communication link between the distant measurement PC and a local operator PC to enable manual or automatic transfer of measured data. The set up for two commercial communication programs, PC Tools Commute and Norton pcAnywhere, are described. |
TN-3.pdf (232 kB) |
| Technote 2: Generating Group Delay vs. Frequency Plots Plots of group delay versus frequency are useful in filter design and loudspeaker design applications. This Technote includes a BASIC program that will use a phase versus frequency plot as generated by System One to produce a group delay plot. The BASIC program can be run in a DOS shell within S1.exe. |
TN-2.pdf (184 kB) All files (148 kB) |
| Technote 1a: Generating Impedance vs. Frequency Plots with APWIN This Technote is a rewrite of Technote #1 to support System One and System Two using Windows APWIN software. An additional method using an external amplifier and current sense resistor is provided. |
TN-1a.pdf (191 kB) All files (114 kB) |
| Technote 1: Generating Impedance vs. Frequency Plots with System One Describes how to generate Impedance versus Frequency swept data using System One. This is of particular interest to loudspeaker designers where the impedance response can provide very useful information on the performance of a speaker. Includes a BASIC program that does the calculations. |
TN-1.pdf (176 kB) All files (139 kB) |
| Appnote 6: Digital Audio Broadcast Receiver Audio Testing
Solve DAB testing problems faster Testing Digital Audio Receivers can be difficult and time-consuming when the audio test signals must be applied to the receiver by means of a synthesized stimulus from an RF signal generator. Audio Precision provides more flexible alternatives with testing techniques that address such solutions as:
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AN-6.pdf (381 kB) |
| Appnote 1: Compact Disc Player Tests Application Note 1b is an addendum to Application Note 1a, providing support beyond System Two and adding 96 kHz SR capability and other improvements. Together with the original Application Note 1a, Compact Disc Player Tests provides common tests such as frequency response, harmonic and intermodulation distortion, and signal-to-noise ratio. The Application Note also shows how to measure quantization distortion and noise (mechanisms not present in analog audio devices) plus ultra-wide-range linearity.The "All files" link at left includes PDFs for both 1a and 1b, and supporting test and macro files. |
AN-1b.pdf (153 kB) ReadMe.pdf (218kB) AN-1a.pdf (1.22MB) All files (2.2 MB) |