Stanford Research Systems QCM200 Data Generator
The Stanford Research SR844 is a high-performance 200 MHz lock-in amplifier designed for precision measurement of signals in noisy environments. It features a wide frequency range, excellent dynamic reserve, and versatile signal processing capabilities. Ideal for scientific research and engineering applications requiring sensitive signal detection.
- Model
- Stanford Research Systems SR844
- Calibration
- Available on request
- Price
- $6,779
- Status
- In stock
- RFQ ref
- SR844
This unit
The Stanford Research SR844 200 MHz Lock-In Amplifier delivers high-performance signal detection across RF frequencies from 25 kHz to 200 MHz. Built on proven Digital Signal Processing architecture, this instrument combines exceptional sensitivity with dynamic reserve up to 80 dB, making it suitable for precision measurements in noise-rich environments.
Technical Specifications
Signal Input
- Single-ended BNC connector with selectable input impedance: 50 Ω or 1 MΩ + 30 pF
- Bandwidth: 25 kHz to 200 MHz
- Damage threshold: ±5 V (DC + AC)
- Full-scale sensitivities: 100 nVrms to 1 Vrms, spanning –127 dBm to +13 dBm
- Gain accuracy: ±0.25 dB below 50 MHz; ±0.50 dB below 200 MHz
- Gain stability: 0.2 %/°C
- RF attenuation/gain: 60 dB attenuation or 20 dB gain in 20 dB steps
- Input noise floor: 2 nV/√Hz typical (50 Ω); 5 nV/√Hz typical (1 MΩ)
- Coherent pickup: <100 nV typical below 10 MHz; <2.5 µV below 50 MHz; <25 µV below 200 MHz
Reference Channel
- External reference: 25 kHz to 200 MHz with 50 Ω or 10 kΩ + 40 pF impedance; accepts 0.7 Vpp pulses or 0 dBm sine waves
- Internal reference: 25 kHz to 200 MHz with 3-digit frequency resolution and ±0.1 accuracy in the 3rd digit
- Harmonic detection at 2F from 50 kHz to 200 MHz
- Front panel reference output: 25 kHz to 200 MHz square wave, 1.0 Vpp nominal into 50 Ω
- Rear panel TTL output: 25 kHz to 1.5 MHz, 0 to +5 V nominal
Output Filters
- Time constants: 100 µs to 30 ks with selectable rolloff: 6, 12, 18, or 24 dB/octave
- Key Features
- Low zero-drift for stable dc-coupled measurements
- Precise RF phase shifting capability
- Digital output filtering with multiple time constant options
- Automatic reference acquisition below 10 s; sub-1 s within same frequency octave
- Dynamic reserve supports measurement of signals masked by noise up to 80 dB stronger
- Typical Applications
Optical heterodyne detection, phase-sensitive RF measurements, weak-signal spectroscopy, and precision impedance characterization in the 25 kHz to 200 MHz band.
Specifications
| Parameter | Value |
|---|---|
| Frequency Range | 25 kHz to 200 MHz | Power Range (dBm): –127 dBm to +13 dBm | Voltage / Current Range: ±5 V damage threshold |
Stanford Research Systems SR844 — Repair & Calibration Service
Aumictech offers NIST-traceable calibration and repair for the Stanford Research Systems SR844. Calibration covers calibration scope varies by instrument type: vacuum gauges are verified at multiple pressure points against NIST-traceable pressure standards; spectrophotometers at wavelength accuracy and photometric accuracy points; strain gauge indicators at bridge excitation accuracy and full-scale output accuracy; pH meters against certified buffer solutions at pH 4, 7, and 10.. All calibrations ship with a NIST-traceable certificate. Turnaround is typically 1–3 business days after receipt.
Common Stanford Research Systems SR844 faults: vacuum gauge filament failure (ionization gauges), spectrophotometer D2 lamp end-of-life, wavelength motor failure, strain indicator front-panel binding post corrosion, pH electrode conditioning failure. Most specialty laboratory instruments fail at their electromechanical interfaces first — vacuum gauge connectors and filament assemblies, spectrophotometer lamp housings and motor drives, strain indicator binding post corrosion. Component-level repair is standard; manufacturer support for legacy instruments is often limited, making third-party bench repair the practical path.
Stanford Research Systems SR844 price
This Stanford Research Systems SR844 is listed at $6,779. Calibration is available separately from $450. Contact us for volume pricing or if you need multiple units.
Stanford Research Systems SR844 calibration cost
NIST-traceable calibration for the Stanford Research Systems SR844 is $450 (standard — pass/fail certificate and calibration sticker) or $650 (full measured data at every test point, reference standards documented, traceability chain included). Calibration for this instrument covers calibration scope varies by instrument type: vacuum gauges are verified at multiple pressure points against NIST-traceable pressure standards; spectrophotometers at wavelength accuracy and photometric accuracy points; strain gauge indicators at bridge excitation accuracy and full-scale output accuracy; pH meters against certified buffer solutions at pH 4, 7, and 10.. Turnaround is 1 to 3 business days after receipt. See full calibration details →
