SIGNAL CHANNEL Voltage Inputs Single-ended (A) or differential (A-B). Current Input 106 or 108 Volts/Amp. Full Scale Sensitivity 2 nV to 1 V in a 1-2-5-10 sequence (expand off). Input Impedance Voltage: 10 MΩ+25 pF, AC or DC coupled. Current: 1 kΩ to virtual ground. Gain Accuracy ±1% from 20°C to 30°C (notch filters off), ±0.2% Typical Input Noise 6 nV/√Hz at 1 kHz (typical). Signal Filters 60 (50) Hz and 120(100) Hz notch filters (Q=4). CMRR 100 dB at 10 kHz (DC Coupled), decreasing by 6 dB/octave above 10 kHz Dynamic Reserve Greater than 100 dB (with no signal filters). Harmonic Distortion -80 dB. REFERENCE CHANNEL Frequency Range 1 mHz to 102 kHz Reference Input TTL (rising or falling edge) or Sine. Sine input is1 MΩ, AC coupled (>1 Hz). 400 mV pk-pk minimum signal. Phase Resolution 0.01° Absolute Phase Error <1° Relative Phase Error <0.01° Phase Noise External synthesized reference: 0.005° rms at 1 kHz, 100 ms, 12 dB/oct. Internal reference: crystal synthesized, <0.0001° rms at 1 kHz. Phase Drift <0.01°/°C below 10 kHz <0.1°/°C to 100 kHz Harmonic Detect Detect at Nxf where N<19999 and Nxf<102 kHz. Acquisition Time (2 cycles + 5 ms) or 40 ms, whichever is greater. DEMODULATOR Zero Stability Digital display has no zero drift on all dynamic reserves. Analog outputs: <5 ppm/°C for all dynamic reserves. Time Constants 10 μs to 30 s (reference > 200 Hz). 6, 12, 18, 24 dB/oct rolloff. up to 30000 s (reference < 200 Hz). 6, 12, 18, 24 dB/oct rolloff. Synchronous filtering available below 200 Hz. Harmonic Rejection -80 dB INTERNAL OSCILLATOR Frequency 1 mHz to 102 kHz. Frequency Accuracy 25 ppm + 30 μHz Frequency Resolution 4 1/2 digits or 0.1 mHz, whichever is greater. Distortion f<10 kHz, below -80 dBc. f>10 kHz, below -70 dBc.1 Vrms amplitude. Output Impedance 50 Ω Amplitude 4 mVrms to 5 Vrms (into a high impedance load) with 2 mV resolution. (2 mVrms to 2.5 Vrms into 50 Ω load). Amplitude Accuracy 1% Amplitude Stability 50 ppm/°C Outputs Sine output on front panel. TTL sync output on rear panel. When using an external reference, both outputs are phase locked to the external reference. DISPLAYS Channel 1 4 1/2 digit LED display with 40 segment LED bar graph. X, R, X Noise, Aux Input 1 or 2. The display can also be any of these quantities divided by Aux Input 1 or 2. (Y and q are available over the interface only.) Offset X, Y and R may be offset up to ±105% of full scale. (Y via interface only) Expand X, Y and R may be expanded by 10 or 100. (Y via interface only) Reference 4 1/2 digit LED display. Display and modify reference frequency or phase, sine output amplitude, harmonic detect, offset percentage (Xor R), or Aux Outputs 1-4. Data Buffer 8k points from Channel 1 display may be stored internally. The internal data sample rate ranges from 512 Hz down to 1 point every 16 seconds. Samples can also be externally triggered. The data buffer is accessible only over the computer interface. INPUTS AND OUTPUTS Channel 1 Output Output proportional to Channel 1 display, or X. Output Voltage: ±10 V full scale. 10 mA max output current. X and Y Outputs Rear panel outputs of cosine (X) and sine (Y) components. Output Voltage: ±10 V full scale. 10 mA max output current. Aux. Outputs 4 BNC Digital to Analog outputs. ±10.5 V full scale, 1 mV resolution. 10 mA max output current. Aux. Inputs 4 BNC Analog to Digital inputs. Differential inputs with1 MΩ input impedance on both shield and center conductor. ±10.5 V full scale, 1 mV resolution. Trigger Input TTL trigger input triggers stored data samples. Monitor Output Analog output of signal amplifiers (before the demodulator). GENERAL Interfaces IEEE-488 and RS-232 interfaces standard. All instrument functions can be controlled through the IEEE-488 and RS-232 interfaces. Preamp Power Power connector for SR550 and SR552 preamplifiers. Power 40 Watts, 100/120/220/240 VAC, 50/60 Hz. Dimensions 17"W x 5.25"H x 19.5"D Weight 30 lbs. Warranty One year parts and labor on materials and workmanship.