SR1 Audio Analyser

SR1 Audio Analyser

SR1 Dual-Domain Audio Analyzer — high performance audio analysis at a very affordable price.

SR1 200 kHz dual-domain audio analyzer
  • -112dB THD+N (1kHz,20kHz BW))
  • 200kHz frequency range
  • +/-0.008 dB flatness
  • -118dBu analyser noise (20kHz BW)
  • -140dB input crosstalk
  • 24-bit/192kHz digital audio
  • <600ps residual jitter
  • Dual channel FFT & Cross-domain analysis

Description

SR1 is a stand-alone instrument that delivers cutting edge performance in a wide variety of audio measurements. With a versatile high-performance generator, an array of analyzers that operate symmetrically in both the analog and digital domains, and digital audio carrier measurements at sampling rates up to 192 kHz, SR1 is the right choice for the most demanding analog and digital audio applications.

User Interface

SR1 Front Panel

SR1 uses an integrated computer running the Windows XP embedded operating system, so operation will be immediately familiar and intuitive. Depending on the application, SR1 can be operated with an external mouse and keyboard, or by using the front-panel knob, keypad and touchpad.

SR1 Rear Panel

Seven on-screen tabbed pages are available for arranging panels, graphs, and displays. Screen setups, data, and instrument configurations can be quickly saved and recalled to either the internal hard disk or to a flash drive connected to one of the two front-panel USB connectors. An optional 1024 × 768 XVGA monitor (opt. 02) provides better resolution and allows more information to be displayed.

While SR1’s configuration panels offer total flexibility in setting up every detail of the analyzer, at times it is useful to get a measurement going quickly, without worrying about infrequently used parameters. That’s where QuickMeas comes in. QuickMeas gives SR1 users the ability to get up and running on many common audio measurements such as Level, SNR, Frequency Response, and Crosstalk after answering just a few simple questions about the inputs and outputs of the DUT. When the measurements are finished, the results are available in a clear, easy-to-understand report.

Analog Signal Generator

Analog & Digital Signal Generator Panels

At the heart of SR1 is a uniquely flexible analog signal generator. All of the standard audio waveforms are available including sine, log-swept sine chirp, synchronous burst sine, noise (white, pink, and filtered), standard intermodulation test signals (SMPTE, CCIF, DIM), square waves, arbitrary waveforms (ASCII and .WAV), ramps, MLS and multitone waveforms. Many of these signals can be combined in the generator allowing you to create an unlimited number of test waveforms.

But the analog signal generator doesn’t sacrifice performance for flexibility. With a flatness of ±0.008 dB (20 Hz to 20 kHz) and a residual THD + N of –106 dB (20 Hz to 20 kHz), SR1’s Low Distortion Sine rivals the performance of any analyzer.

Multitone waveforms with up to 50 tones, each adjustable in frequency, amplitude, and phase are calculated and loaded in real-time, without having to run a cumbersome off-line program to generate arbitrary waveform tables. A convenient FFT Chirp waveform is automatically synchronized to the FFT analyzer allowing instant FFT measurements of frequency response (magnitude and phase).

Digital Audio Signal Generator

Digital I/O Panels

The same flexibility and performance is found in SR1’s digital audio signal generator. Almost all the same waveforms found in the analog generator are available in the digital generator with the addition of several special digital test waveforms including digital constant, walking bits, and a staircase waveform (for D/A testing).

The digital audio output sampling rate is continuously adjustable from 24 kHz to 216 kHz (single and dual connector). Full control over transmitted status bits (in both professional and consumer formats), user bits, and validity bits, is provided.

For digital interface testing, a variety of impairment signals can be imposed on the digital audio carrier. Carrier impairments include variable rise time (5 ns to 400 ns), common mode sine waves, normal mode noise, and several jitter waveforms (sine, square, and noise).

Timebase

All of SR1’s sampling clocks are derived from an internal timebase with 5 ppm accuracy. For the most demanding applications, an optional atomic rubidium (PERF10) timebase is available with an accuracy at shipment of ±5 × 10–11, and a 20-year aging specification of less than 5 ppb. Additionally, the timebase may be synchronized to an external clock, an AES11 reference signal, or any standard video signal.

Analyzers

The heart of SR1’s measurement abilities is its versatile set of analyzers which operate symmetrically on both analog and digital audio signals with no need to purchase additional options. Up to two analyzers can be run simultaneously on either the analog or digital inputs.

The Time Domain Detector makes all of the standard audio measurements including Amplitude, Crosstalk, and THD + N. Continuously variable bandwidth limiting and standard weighting filters are included. The post notch-filter distortion signal can be fed to an FFT analyzer for a live spectral display of distortion, or to the rear-panel monitor output or speaker.

The Single-Channel FFT and Dual-Channel FFT analyzers offer live spectral displays with full zoom and heterodyne capability. The full resolution of the analyzer can be applied to any frequency range down to 1/512th of the full measurement bandwidth, leading to an effective resolution of 16M FFT lines. Several averaging algorithms can be applied to bring out low level signals.

The two-channel FFT analyzer offers true single-shot frequency response measurements for the ultimate in accuracy. SR1 also has a complete set of impulse response measurements including impulse response, quasi-anechoic frequency response, and energy time-curve. Since SR1 is a true two-channel FFT, it isn’t limited to MLS waveforms, but can use virtually any waveform.

The THD Analyzer makes frequency selective THD measurements on two user-selectable sets of up to thirteen harmonics of the input signal.

The IMD Analyzer makes standard audio distortion measurements including SMPTE, CCIF, and DIM. Frequency selective analysis ensures high measurement accuracy.

The Histogram Analyzer displays live histograms of input signal amplitudes and probability distributions. Realtime fits to Gaussian distributions can be generated.

The Multitone Analyzer, in combination with the Multitone Generator, can be configured to make fast single-shot measurements of a variety of audio parameters including Level, Frequency Response, THD + N, THD, Total Distortion, Noise, Crosstalk, and IMD.

Digital Audio Interface Measurements

SR1 provides a complete set of measurements for digital interface testing. Carrier level and sampling frequency are measured directly. Status bits are fully decoded in both professional and consumer formats, and user bits are displayed as well. SR1’s Jitter Analyzer measures jitter in both the time and frequency domain, including continuously variable bandwidth limiting and weighting in both domains. For frequency domain measurements, live zoomable and heterodyned spectral displays of jitter are available. Using the jitter chirp waveform, you can characterize jitter transfer functions in under a second. With a residual jitter of only 600 ps, the performance of SR1’s jitter analyzer is unbeatable.

Digitizer

Eye Diagram

An optional 80 MHz transient digitizer (Opt. 01) provides additional digital audio carrier analysis. Operating on a record SR1 Audio Analyzer of up to 2M samples, the digitizer computes and displays the time record of the input signal and its jitter, input spectrum, jitter spectrum, and the probability distributions of the input and jitter amplitudes as well as the pulse width and pulse rate. Full color eye-diagrams can be generated allowing easy testing against user-configurable eye limits.

Automation and Programming

remote programming. On-board scripts can be written in VBScript, Jscript, or Python with full access to all of the instrument’s capabilities as well as the ability to create simple user-interfaces for running tests. SR1 has a complete hierarchical GPIB command set, and GPIB commands can be sent over the standard IEE-488 interface, RS-232 port, or over the Ethernet on a TCP/IP network (VXI-11). Finally, SR1 has a complete COM interface allowing instrument operation to be automated from any COM capable application such as Visual Basic, LabView, or Microsoft Office.

Learning Mode

Learning mode is a powerful tool for quickly creating scripts without detailed knowledge of the programming environment. SR1 creates a script by recording each keystroke or user operation, and then converts the script to a VB script or Jscript program. These programs can be saved and edited like any other script, then run in the future.

Specifications

Analog Signal Generator

General Characteristics
Amplitude Range

Amplitude Accuracy
Frequency Range
  High BW DAC
  High Res. DAC

Frequency Accuracy
Frequency Resolution
Output Configuration

Source Impedance
Max. Power (600 Ω load)
  Balanced
  Unbalanced
Float Voltage
Crosstalk
  10 Hz to 20 kHz
  >20 kHz
1 µV to 28.8 V (balanced)
1 µV to 14.4 V (unbalanced)
±0.5 % (±0.43 dB) at 1 kHz

10 Hz to 200 kHz
10 Hz to 0.45Fs (Fs: 128 kHz or
64 kHz fixed, 24 kHz to 216 kHz adj.)
±0.0005% (5 ppm)
6-digit
Balanced Ground, Balanced Float, Unbalanced Ground, Unbalanced Float, Common Mode Test
50 Ω, 150 Ω, 600 Ω (balanced)
25 Ω, 75 Ω, 600 Ω (unbalanced)
30.5 dBm
24.9 dBm
±40 V

-125 dB
-100 dB
Waveforms
Low Distortion sine
Flatness
  20 Hz to 20 kHz
  10 Hz to 64 kHz
  10 Hz to 200 kHz
Residual THD+N
  1 kHz, 4Vrms
  20 Hz to 20 kHz


  10 Hz to 100 kHz

±0.020 dB (typ ±0.012 dB)
±0.025 dB
±0.05 dB

-112 dB (22 kHz BW)
-106 dB + 1µV (22 kHz BW)
-105 dB + 1.7µV (80 kHz BW)
-97 dB + 2.5µV (200 kHz BW)
-89 dB + 2.5µV (200 kHz BW)
Normal Sine
Flatness
  20 Hz to 20 kHz
  10 Hz to 64 kHz
  10 Hz to 200 kHz
Residual THD + N (Hi BW DAC)
  1 kHz
  22 Hz to 20 kHz
  
  
  10 Hz to 100 kHz
Residual THD + N (Hi Res DAC, Fs = 128 kHz))
  1 kHz
  22 Hz to 20 kHz
  20 Hz to 57.6 kHz
Residual THD + N (Hi Res DAC, Fs = 64 kHz))
  1 kHz
  20 Hz to 20 kHz
Phased Sines
IMD
Noise
Multitone
MLS
FFT Chirp
Log-sine chirp
Square
Ramp
Arbitrary
Polarity
Constant (Offset)
Bursts
Burst Types

±0.008 dB (typ. ±0.003 dB)
±0.02 dB
±0.03 dB

–86 dB (22 kHz BW)
–85 dB + 1 µV (22 kHz BW)
–84.5 dB + 1.7 µV (80 kHz BW)
–82 dB + 2.5 µV (200 kHz BW)
–77 dB + 2.5 µV (200 kHz BW)

–99 dB (22 kHz BW)
–98 dB + 1 µV (22 kHz BW)
–96.5 dB + 1.4 µV (57.6 kHz BW)

–106 dB (22 kHz BW)
–101 dB + 1 µV (22 kHz BW)
0 to 360°, 0.001° resolution
SMPTE/DIN, CCIF/DFD, DIM/TIM
White, Pink, Filtered White/Pink, USASI
1 to 50 tones
Repetition rates from 2&sup8; to 20²0;
Equal power in each FFT bin.
Swept-sine w/log increasing frequencies
10 Hz to 50 kHz frequency range
Fs/N frequency range (N=20)
256 Samples to 136k Samples
10 Hz to Fs/4 frequency range
DC to 20 Vp (unbal) / 40 Vp (bal)

Timed, externally triggered, externally gated

Digital Audio Signal Generator

Digital Audio Carrier Characteristics
Output Amplitude
  Balanced
    Range
    Accuracy
  Unbalanced
    Range
    Accuracy
Output Format


Output Sample Rate
Sample Rate Accuracy
Output Impedance

16 mV to 10.2 V (110 Ω load)
±10 % + 80 mV

4 mV to 2.55 V (75 Ω load)
±10 % + 20 mV
Balanced XLR (AES/EBU), dual-connector XLR, unbalanced BNC (SPDIF-EIAJ),dual-connector BNC, Optical (Toslink)
24 kHz to 216 kHz
±5 ppm
110 Ω (balanced), 75 Ω (unbalanced)
Digital Audio Waveforms
Sine
  Frequency Range
  Frequency Resolution
  Flatness
  Harmonic/Spurious
Phased Sine
Square
IMD
Noise
MLS [brRamp
Arbitrary
FFT Chirp
Log-swept sine chirp
Polarity
Bursts
Burst Waveforms
Burst Types
Digital Test Waveforms

Dither


10 Hz to Fs/2
6-digit
±0.001 dB
-148 dB
0 to 360° range, 0.01° resolution
10 Hz to Fs/2 frequency range
SMPTE/DIN, CCIF/DFD, DIM/TIM
White, Pink, Filtered White/Pink, USASI
Repetition rates from 28 to 220
Fs/N frequency range (N=20)
256 Samples to 136k Samples
Equal power in each FFT bin
Swept-sine with log increasing frequencies
10 Hz to Fs/4 frequency range

All allowed waveforms
Timed
Digital Constant, Count, Rotating Bits,
Staircase, J-Test
None, triangle and rectangular probability distribution
Digital Audio Carrier Impairments
Jitter
  Waveforms
  Frequency Range
  Amplitude Range
Normal Mode Noise
  Amplitude Range
    Unbalanced
    Balanced
Common Mode Sine
Amplitude Range
Frequency Range
Cable Simulation
Variable Rise Time

Sine, square, uniform noise, BP filtered noise
2 Hz to 200 kHz
0 UI to 13 UI


0 to 637 mVpp
0 to 2.55 Vpp

0 to 20 Vpp (balanced only)
10 Hz to 100 kHz
Simulates 100 m of digital audio cable
5 ns to 400 ns

Signal Measurements

General Analog Input Characteristics
Amplitude Range (rms)
Input Configuration

Input Impedance
  Balanced
  Unbalanced
Input Termination
Crosstalk
  10 Hz to 50 kHz
  >50 kHz
Hi BW ADC
  Type
  Sampling Frequency
  Frequency Range
Hi Resolution ADC
  Type
  Sampling Frequency
  Frequency Range
62.5 mV to 160 V
XLR, BNC, Generator Monitor, Digital Audio Common Mode

200 kΩ / 95 pF
100 kΩ / 185 pF
300 Ω, 600 Ω, 200 Ω

≤-140 dB
≤-135 dB

16-bit sigma-delta
512 kHz
DC to 228 kHz

24-bit sigma-delta
128 kHz or 64 kHz (fixed), 24 kHz to 216 kHz (adj.)
DC to 0.45Fs
General Digital Input Characteristics
Input Format


Input Sample Rate
Input Impedance
Balanced XLR (AES/EBU), dual-connector XLR, unbalanced BNC (SPDIF-EIAJ), dual-connector BNC, Optical (Toslink)
24 kHz to 216 kHz
Hi Z or 110 Ω (balanced)
Hi Z or 75 Ω (unbalanced)
Analog Signal Meters
RMS Level Meter
  Accuracy
  Flatness
    20 Hz to 20 kHz
    10 Hz to 64 kHz
    10 Hz to 200 kHz
Frequency Meter
  Range
  Accuracy
Phase Meter
(1 kHz ref) ±0.5 % (±0.043 dB)
(1 kHz ref, amplitude less than 4 Vrms)
<±0.008 dB(typ. <±0.003 dB)
<±0.02 dB
<±0.03 dB

8 Hz to 300 kHz
timebase error ±2 ppm +10 mHz)
±1.0°
Digital Signal Meters
Frequency Meter
Phase Meter
10 Hz to 0.45Fs, ±100 ppm accuracy
±0.05° accuracy
Analyzers (Analog and Digital Audio)
Time Domain Analyzer
Measurements

Amplitude, amplitude ratio, THD+N, THD+N ratio
SINAD, Crest Factor
Analog Inputs
Amplitude Accuracy
Flatness (1 kHz ref)
  50 Hz to 20 kHz
  20 Hz to 64 kHz
  10 Hz to 200 kHz
±0.5 % (±0.043 dB)

<±0.008 dB
<±0.02 dB
<±0.05 dB
Residual Noise ((62.5 Vrms input range, shorted input)
  High Res. ADC (Fs=128 kHz)
    22 Hz to 22 kHz
    22 kHz to 57.6 kHz
    A-Weighted
  High BW ADC
    22 Hz to 22 kHz
    22 Hz to 80 kHz
    22 Hz to 200 kHz
    A-Weighted

-117.5 dBu
-115 dBu
-120 dBu

-118 dBu
-113 dBu
-110 dBu
-120 dBu
Residual THD+N
  High Res. ADC (Fs=128 kHz)
    1 kHz. 4 Vrms
    20 Hz to 20 kHz

  High Res ADC (Fs=64kHz
    1 kHz, 4Vrms
    20 Hz to 20 kHz
  High BW ADC
    1 kHz, 4Vrms
    20 Hz to 20 kHz

    10 Hz to 100 kHz

-111 dB (22 kHz BW)
-107 dB + 0.8 µV (22 kHz BW)
-101 dB + 1.3 µV(57.6 kHz BW)

-111 dB (22 kHz BW)
-107 dB + 0.8 µV (22 kHz BW)

-113 dB (22 kHz BW),
-109 dB + 0.8 µV (22 kHz BW)
-102 dB + 1.5 µV (80 kHz BW)
-91 dB (200 kHz BW)
Digital Inputs
Amplitude Accuracy
Flatness
Residual THD+N
±0.001 dB (at 1 kHz)
±0.001 dB (15 Hz to 22 kHz)
-140 dBFS
Bandwidth Limiting Filters
  Low Pass Filter


  High Pass Filter


  Band Pass Filter
    Response
      Hi BW ADC
      Hi RES ADC
    Tuning Range
      Hi BW ADC
      Hi RES ADC
    Tuning Accuracy
    Amplitude Accuracy
Notch filters
  Tuning range
   ,Hi BW ADC
   ,Hi Res ADC
  Tuning accuracy
  Response
  Ampl. accuracy

Weighting Filters

Detector Type
4th order Butterworth, adj. from Fs/40 to 0.45Fs,
20 kHz, 40 kHz and 80 kHz fixed elliptical filters
per AES17
4th order Butterworth, @22 Hz, 100 Hz, and 400 Hz.
20 kHz, 40 kHz and 80 kHz fixed elliptical filters
per AES17


1/3 Octave, Class II (4-pole)
1/3, 1/6, 1/12, 1/24 Octave, Class III (6-pole)

10 Hz to 200 kHz
10 Hz to 0.44Fs
±2.5 %
±0.5 %


10 Hz to 200 kHz
10 Hz to 0.44Fs
±2.5 %
–3 dB at 0.73 Fc and 1.37 Fc
±0.2 dB (20 Hz to 180 kHz,
f < 0.5f0 or f > 2f0)
A-wt, C-Msg wt, CCITT, CCIR
(weighted, unweighted, & 2 kHz)
RMS, Peak, Quasi-Peak (CCIR-468)
Single and Dual-Ch. FFT Analyzers
Frequency Range
  Hi BW ADC
  Hi Res ADC
Number of Lines
Processing
Windows


Zoom
Heterodyne

Averaging
Dual-Ch. Measurements


THD Analyzer

IMD Analyzer
Histogram Analyzer

Multitone Analyzer

DC to 200 kHz
DC to 0.45Fs
256, 512, ... 32k
40-bit floating point
Blackman Harris, Enhanced Blackman Harris, Hann,
Hamming, Equiripple, Flattop, Gaussian, Kaiser,
Uniform, Rife Vincent 4, 5 & 10 term
Span can be narrowed by up to 512x
Narrowed span can be centered anywhere
in the measurement range
Fixed length and continuous
Frequency, Impulse and Quasianechoic
Response, Coherence,
Energy Time Curve, Group Delay
Measures two independent sets of user-
selectable harmonics (2x to 14x)
SMPTE/DIN, CCIF/DFD, DIM/TIM
Time vs. amplitude, Histogram,
PDF, Gaussian fit to PDF
Level, Frequency Response, THD+N,
noise, THD, IMD, Crosstalk

Digital Audio Carrier Measurements

Measurements

Sample Rate
Sample Rate Accuracy
Carrier Amplitude Measurements
  Balanced (XLR)
  Unbalanced (BNC)
Optical
Output to Input Delay

  Range
  Resolution
Residual Jitter
  50 Hz to 100 kHz
Carrier amplitude, sample rate, jitter amplitude,
jitter spectrum
24 kHz to 216 kHz
±5 ppm


±10 % + 80 mV
±10 % + 20 mV
Displays voltage of Toslink receiver
Measures delay from Digital Audio Output or AES11 reference output to Digital Audio Input
–12.7 UI to +115.1 UI in seconds
60 ns

≤600 ps
Reference
Input Sources


Reference Output
AES11 (24 Hz to 216 kHz),
sine or TTL (8 kHz to 32 MHz),
video (NTSC/PAL/SECAM)
AES11 (24 to 216 kHz)
Optional Digitizer (Opt.1)
Sampling Rate
Acquisition Length
Measurements
80 MHz
4k, 8k, 16k, 128k, 256k, 512k, 1M, 2M samples
Input vs. time, jitter vs. time, input spectrum, jitter spectrum, pulse width/rate histograms, jitter probability histogram, eye diagrams

General

Computer Interfaces
Video Out
Power
Dimensions
Weight
Warranty
GPIB, RS-232, Ethernet, COM.
VGA output for driving external monitor
<250 W, 90 to 264 VAC, 47 Hz to 63 Hz
17" × 8.5 " × 20.25 " (WHD)
40 lbs
One year parts and labor on defects in materials and workmanship