SR785 – 100 kHz 2-ch. FFT analyzer

Technical Specifications

Measurement Groups
Groups: FFT, Correlation, Time Histogram, Swept-Sine, Order Tracking

Frequency
Range: 102.4 kHz or 100 kHz (both displays have the same range)
FFT spans: 195.3 mHz to 102.4 kHz or 191 mHz to 100 kHz. The two displays can have different spans and start frequencies.
FFT resolution: 100, 200, 400 or 800 lines
Real-time bandwidth: 102.4 kHz (highest FFT span with continuous data acquisition and averaging)
Accuracy: 25 ppm from 20 ?C to 40 ?C

Dynamic Range
Dynamic range: 90 dB typical, 80 dB guaranteed (FFT and Octave). 145 dB typical (Swept-Sine). Includes spurs, harmonics, intermodulation distortion, and alias products. Excludes alias responses at extremes of span.
Harmonic distortion: <-80 dB (single tone in band)
Intermod. Distortion: <-80 dB (two tones in band, each less than -6.02 dBfs)
Spurious: <-80 dBfs
Alias responses: <-80 dBfs (single tone outside of span, -30 dBV, Hanning window, 64 rms averages)
Residual DC response: <-30 dBfs (FFT with Auto-Cal on)

Amplitude Accuracy
Single channel: ?0.2 dB (excluding window effects)
Cross channel: ?0.05 dB, DC to 102.4 kHz (frequency response measurement, both inputs on the same range, rms averaged)
Phase Accuracy
Single channel: ?3.0 deg. relative to external TTL trigger (-50 dBfs to 0 dBfs, freq <10.24 kHz, center of frequency bin, DC coupled). For Blackman-Harris, Hanning, Flat-Top and Kaiser windows, phase is relative to a cosine wave at center of time record. For Uniform, Force and Exponential windows, phase is relative to a cosine wave at beginning of the time record.
Cross channel: ?0.5 deg. (DC to 51.2 kHz)
?1.0 deg. (DC to 102.4 kHz)
(frequency response measurement, both inputs on same range, vector averaged)

Signal Inputs
Number of inputs: 2
Full-scale input range: -50 dBV (3.16 mVp) to +34 dBV (50 Vp) in 2 dB steps
Maximum input level: 57 Vp
Input configuration: Single-ended (A) or differential (A-B)
Input impedance: 1 M? + 50 pF
Shield to chassis: Floating mode: 1 M? + 0.01 ?F
Grounded mode: 50 ? (shields grounded in (A-B) mode)
Max. shield voltage: 4 Vp
AC coupling: 0.16 Hz cutoff frequency
CMRR: 90 dB at 1 kHz (input range <0 dBV)
80 dB at 1 kHz (input range <10 dBV)
50 dB at 1 kHz (input range ?10 dBV)
ICP signal conditioning: Current source: 4.8 mA
Open circuit voltage: +26 V
A-weight filter: Type 0 tolerance, ANSI standard S1.4-1983; 10 Hz to 25.6 kHz
Crosstalk: <-145 dB below signal (input to input and source to inputs, 50 ? receiving input source impedance)
Input noise: <10 nVrms/?Hz above 200 Hz (<-160 dBVrms/?Hz)

Trigger Input
Modes: Free Run, Internal, External, or External TTL
Internal: Level adjustable to ?100 % of input scale, positive or negative slope. Min. trigger level: 5 % of input range
External: Level adjustable to ?5 V in 40 mV steps, positive or negative slope.
Input impedance: 1 M?
Max. input: ?5 V
Min. trigger amplitude: 100 mV
External TTL: Requires TTL level to trigger (low 3.0 V)
Post-trigger: Measurement record is delayed up to 100,000 samples after the trigger.
Pre-trigger: Measurement record starts up to 8000 samples prior to the trigger.

Tachometer Input
Pulses per revolution: 1 to 2048
RPM accuracy: ?50 ppm (typ.)
Tach level range: ?25 V, ?5 V, TTL
Tach level resolution: 20 mV @ ?25 V, 4 mV @ ?5 V
Max. tach input level: ?40 Vp
Min. tach pulse width: 100 ns
Max. tach pulse rate: 750 kHz (typ.)

Transient Capture
Mode: Continuous data recording
Maximum rate: 262,144 samples/s for both inputs
Maximum capture length: 2 Msamples (single input)
8 Msamples with optional memory
Octave Analysis
Standards: Conforms to ANSI standard S1.11- 1986, Order 3, Type 1-D
Frequency range: (Band centers)

Single channel
1/1 Octave 0.125 Hz to 32 kHz
1/3 Octave 0.100 Hz to 40 kHz
1/12 Octave 0.091 Hz to 12.3 kHz
Two channels
1/1 Octave 0.125 Hz to 16 kHz
1/3 Octave 0.100 Hz to 20 kHz
1/12 Octave 0.091 Hz to 6.17 kHz
Accuracy: <0.2 dB (1 second stable average, single tone at band center)
Dynamic range: 80 dB (1/3 Octave, 2 second stable average) per ANSI S1.11-1986
Sound level: Impulse, Peak, Fast, Slow and Leq per ANSI S1.4-1983 Type 0 and IEC 651-1979 Type 0

Order Tracking
Delta order: 0.0075 to 1
Resolution: up to 400 lines
Amplitude accuracy: ?1 dB (typ.)
Displays: Order map (mag. and phase), order track (mag. and phase), orbit
Curve Fit and Synthesis
Type: 20 poles/20 zeros curve fit (non-iterative rational fraction)
Order selection: Auto or manual
Output format: Pole-zero, polynomial, pole-residue

Source Output
Amplitude range: 0.1 mVp to 5 Vp
Amplitude resolution: 0.1 mVp
DC offset: <10.0 mV (typ.)
Offset adjust: ?5 VDC (sine, two-tone, swept-sine)
Output impedance: <5 ?, ?100 mA peak output current
Sine Source
Amplitude accuracy: ?1 % of setting, 0 Hz to 102.4 kHz , 0.1 Vp to 5 Vp into High-Z load
Harmonics, sub-harm.
& spurious signals: 0.1 Vp to 5 Vp
<-80 dBc (fundamental <30 kHz)
<-75 dBc (fundamental <102 kHz)

Two-Tone Source
Amplitude accuracy: ?1 % of setting, 0 Hz to 102.4 kHz, 0.1 Vp to 5 Vp into High-Z load
Harmonics, sub-harm.: <-80 dBc, 0.1 Vp to 2.5 Vp

White Noise Source
Time Record: Continuous or burst
Bandwidth: DC to 102.4 kHz or limited to span
Flatness: <0.25 dBpp (typ.), 5000 rms averages (<1.0 dBpp (max.))

Pink Noise Source
Bandwidth: DC to 102.4 kHz
Flatness: <2.0 dBpp, 20 Hz to 20 kHz (measured using averaged 1/3 Octave Analysis)

Chirp Source
Time record: Continuous or Burst
Output: Sine sweep across the FFT span
Flatness: ?0.25 dB (1.0 Vp)

Swept-Sine Source
Auto functions: Source Level, Input Range and Frequency Resolution
Dynamic range: 145 dB

Arbitrary Source
Amplitude range: ?5 V
Record length: 2 Msamples (playback from arbitrary waveform memory or capture buffer). Variable output sample rate.

General
CRT monitor: Monochrome, 800H by 600V resolution
Interfaces: IEEE-488.2, RS-232 and Printer interfaces standard. All instrument functions can be controlled through computer interfaces. A PC (XT) keyboard input is provided for additional flexibility.
Hardcopy: Print to dot matrix and PCL compatible printers. Plot to HP-GL or postscript plotters. Print/plot to RS-232 or IEEE-488.2 interfaces or to disk file. Additional file formats include GIF, PCX and EPS.
Data storage: USB drive
Preamp power: Power connector for SRS preamps
Power: 70 W, 100/120/220/240 VAC, 50/60 Hz
Dimensions: 17″” ? 8.25″” ? 24″” (WHL)
Weight: 56 lbs.
Warranty: One year parts and labor on defects in materials and workmanship

 

Others

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