Stanford CG635 Synthesized Clock Generator

2 GHz low-jitter clock generator

Stanford Research

Distributed only in Germany
This is a discontinued product
More Information? Please contact us.
  • Overview

Key Facts

  • Clocks from 1 µHz to 2.05 GHz
  • Random jitter <1 ps rms
  • 16 digits of frequency resolution
  • 80 ps rise and fall times
Down to Key Facts

Features & Benefits

The CG635 generates extremely stable square wave clocks between 1 µHz and 2.05 GHz.

Specifications

Frequency
Range DC, 1 µHz to 2.05 GHz
Resolution 16 digits (f = 10 kHz), 1 pHz (f < 10 kHz)
Down to Specifications

Key Facts

  • Clocks from 1 µHz to 2.05 GHz
  • Random jitter <1 ps rms
  • 16 digits of frequency resolution
  • 80 ps rise and fall times
  • CMOS, PECL, ECL, LVDS, RS-485 outputs
  • Phase control and time modulation
  • PRBS for eye-pattern testing (opt.)
  • OCXO and rubidium timebase (opt.)

Features & Benefits

  • The CG635 generates extremely stable square wave clocks between 1 µHz and 2.05 GHz. The instrument’s high frequency resolution, low jitter, fast transition times, and flexible output levels make it ideal for use in the development and testing of virtually any digital component, system or network.

    Clean clocks are critical in systems that use high-speed ADCs or DACs. Spurious clock modulation and jitter create artifacts and noise in acquired signals and in reconstructed waveforms. Clean clocks are also important in communications systems and networks. Jitter, wander, or frequency offsets can lead to high bit error rates, or to a total loss of synchronization. The CG635 can provide the clean, stable clocks required for the most critical applications.

Specifications

Frequency
Range DC, 1 µHz to 2.05 GHz
Resolution 16 digits (f = 10 kHz), 1 pHz (f < 10 kHz)
Accuracy Δf < ±(2× 10-19 + timebase error) × f
Settling time <30 ms

Timebase (20 °C to 30 °C ambient)
Stability
<5 ppm (std. timebase)
<0.01 ppm (opt. 02 OCXO)
<0.0001 ppm (opt. 03 Rb timebase)
Aging
<5 ppm/year (std. timebase)
<0.2 ppm/year (opt. 02 OCXO)
<0.0005 ppm/year (opt. 03 Rb timebase)
External input 10 MHz ± 10 ppm, sine >0.5 Vpp, 1 kΩ
Output 10 MHz, 1.41 Vpp sine into 50 Ω

Phase Noise (at 622.08 MHz)
100 Hz offset < -90 dBc/Hz
1 kHz offset < -100 dBc/Hz
10 kHz offset < -100 dBc/Hz
100 kHz offset < -110 dBc/Hz

Jitter and Wander
Jitter (rms) <1 ps (1 kHz to 5 MHz bandwidth)
Wander (p-p) <20 ps (10 s persistence)

Time Modulation (Rear-panel input, 1 kΩ)
Sensitivity 1 ns/V, ±5 %
Range ±5 ns
Bandwidth DC to greater than 10 kHz

Phase setting
Range ±720° (max. step size ±360°)
Resolution <14 ps
Slew time <300 ms

Q and -Q Outputs
Outputs Front-panel BNC connectors
Frequency range DC to 2.05 GHz
High level -2.00 V ≤ VHIGH ≤ +5.00 V
Amplitude 200 mV ≤ VAMPL ≤ 1.00 V
(VAMPL ≡ VHIGH - VLOW)
Level resolution 10 mV
Level error <1 % + 10 mV
Transition time <100 ps (20 % to 80 %)
Symmetry <100 ps departure from nominal 50 %
Source impedance 50 Ω(±1 %)
Load impedance 50 Ω to ground on both outputs
Pre-programmed levels PECL, LVDS, +7 dBm, ECL

CMOS Output
Output Front-panel BNC
Frequency range DC to 250 MHz
Low level -1.00 V ≤ VLOW ≤ +1.00 V
Amplitude 500 mV ≤ VAMPL ≤ 6.00 V
(VAMPL ≡ VHIGH - VLOW)
Level resolution 10 mV
Level error <2 % + 20 mV
Transition time <1 ns (20 % to 80 %)
Symmetry <500 ps departure from nominal 50 %
Source impedance 50 Ω (reverse terminates cable reflection)
Load impedance Unterminated 50 Ω cable of any length
Attenuation (50 Ω load) Output levels are divided by 2
Pre-programmed levels 1.2, 1.8, 2.5, 3.3 or 5.0 V

RS-485 Output
Output Rear-panel RJ-45
Frequency range DC to 105 MHz
Clock output Pin 7 and pin 8 drive twisted pair
Source impedance 100 Ω between pin 7 and pin 8
Load impedance 100 Ω between pin 7 and pin 8
Logic levels VLOW = +0.8 V, VHIGH = +2.5 V
Recommended cable Straight-through Category-6

LVDS Output (EIA/TIA-644)
Output Rear-panel RJ-45
Frequency range DC to 2.05 GHz
Transition time <100 ps (20 % to 80 %)
Clock output Pin 1 and pin 2 to drive twisted pair
Source impedance 100 Ω between pin 1 and pin 2
Load impedance 100 Ω between pin 1 and pin 2
Logic levels VLOW = +0.96 V, VHIGH = +1.34 V
Recommended cable Straight-through Category-6

PRBS (Opt. 01) (EIA/TIA-644)
Outputs PRBS, -PRBS, CLK and -CLK
Frequency range DC to 1.55 GHz
Level LVDS on rear-panel SMA jacks
PRBS generator x7 + x6 + 1 for a length of 27 - 1 bits
Transition time <100 ps (20 % to 80 %)
Load impedance 50 Ω to ground on all outputs

General

Computer interfaces GPIB and RS-232 std. All functions can be controlled through either interface.
Non-volatile memory Ten sets of instrument configurations can be stored and recalled.
Power 90 to 264 VAC, 47 to 63 Hz, 50 W
Dimensions, weight 8.5"× 3.5" × 13" (WHL), 9 lbs.
Warranty One year parts and labor on defects in materials and workmanship
Thank you.

Your request was successfully sent!

We will get in touch with you soon.

Your Rohde & Schwarz Service Team

Feedback
Tell us your opinion
Please tell us which topic.
Please enter your inquiry.
Contact information

Please enter your first name.

Please enter a valid e-mail address.

Please enter your name.
Security Response Code
show captcha

The input was not correct.
*Mandatory Field
Contact Us
Request Information
Thank you.

Your request was successfully sent!

We will get in touch with you soon.

Your Rohde & Schwarz Service Team

Please enter your inquiry.

Please enter your first name.

Please enter your name.

Please enter a valid e-mail address.

Please enter your company name.

Please enter your city name.

Please enter your postal code.

Please enter your country.
show captcha
The input was not correct.
*Mandatory Field
Request a Quote
Thank you.

Your request was successfully sent!

We will get in touch with you soon.

Your Rohde & Schwarz Service Team

Please enter your inquiry.

Please enter your first name.

Please enter your name.

Please enter a valid e-mail address.

Please enter your phone number.

Please enter your company name.

Please enter your city name.

Please enter your postal code.

Please enter your country.
show captcha
The input was not correct.
*Mandatory Field
Request a Demo
Thank you.

Your request was successfully sent!

We will get in touch with you soon.

Your Rohde & Schwarz Service Team

Please enter your inquiry.

Please enter your first name.

Please enter your name.

Please enter a valid e-mail address.

Please enter your company name.

Please enter your city name.

Please enter your postal code.

Please enter your country.
show captcha
The input was not correct.
*Mandatory Field

Downloads
International Website