November 1, 1995
Wenzel Associates introduces a series of phase locked oscillators for military and airborne applications. These oscillators provide very low noise, low spurious outputs at frequencies from 1 to 640 MHz and can be specified to lock to any frequency in the 100 Hz to 100 MHz range. Noise floors of -175 dBc/Hz are available and output spurious may be specified as low as -115 dBc including the input frequency and its products. A specially designed low G sensitivity crystal provides better than 5x10-10 per G performance at 100 MHz, and internal shock mounts are included to minimize vibration induced phase noise above 200 Hz. The oscillators may be configured with multiple outputs and with signal levels to +30 dBm. Prices start at $7000 in single quantities.
March 5, 1996
A series of VHF vibration isolated phase locked oscillators are available for multiplying and filtering noisy frequency standard outputs. The design exhibits excellent immunity to external influences including vibration and line related noise. The output frequency is derived from a crystal operating at one half the output frequency to maximize close-in phase noise performance. The output frequency may be specified between 100 and 200 MHz and the output power may be specified up to +22 dBm with excellent AGC (+- 0.5 dB).
The crystal oscillator is mounted in its own cavity using special omni-directional urethane shock mounts exhibiting excellent performance even at very low temperatures. The isolation system blocks vibration frequencies above 200 Hz which is well below any crystal mechanical resonance giving the unit a nearly resonance-free vibration-induced phase noise profile. A high performance voltage regulator and conditioner gives excellent supply rejection: a 50 millivolt supply ripple from DC to RF causes AM sidebands below -120 dBc.
The PLL typically has a very low bandwidth (near 1 Hz) to take advantage of the crystal's excellent close-in phase noise. The loop settles within 0.1 ppm in 10 seconds. The close-in noise is a function of the design frequency and the noise floor with sinewave outputs is below -165 dBc. The PLL automatically goes to the center frequency in the absence of a reference signal and the free-running frequency stability is +- 15 ppm from -40 to +70 Centigrade. The lock-in range is approximately +- 25 ppm.
RF connector styles are optional. The unit shown in fig. 1 has GPO (Gilbert Engineering Co., Inc.) connectors. Power and control signals are connected via specially filtered pins.
The housing is lightweight Aluminum with a tinned nickel plate.
Also see the Blue Tops vibration isolated oscillator.
February 7, 1996
A series of vibration isolated phase locked oscillators are available for generating very low phase noise outputs from a noisy 5 or 10 MHz reference. The design exhibits excellent immunity to external influences including vibration and line related noise. 12 single-ended or 6 differential outputs are standard. The outputs may be sine, ECL, or capacitively-coupled ECL line drivers (MC10EL89s).
The crystal oscillator is mounted in its own cavity using special omni-directional urethane shock mounts exhibiting excellent performance even at very low temperatures. The isolation system blocks vibration frequencies above 200 Hz which is well below any crystal mechanical resonance giving the unit a nearly resonance-free vibration-induced phase noise profile.
A high performance voltage regulator and conditioner gives excellent supply rejection: a 50 millivolt supply ripple from DC to RF causes AM sidebands below -120 dBc.
The PLL typically has a very low bandwidth (0.1 Hz) to take advantage of the crystal's excellent close-in phase noise. The loop settles within 0.1 ppm in 10 seconds. The close-in noise is a function of the design frequency and the noise floor with sine outputs is below -170 dBc. Spurious signals are below the noise for frequencies below 3 kHz and below -120 dBc for offsets above 3 kHz.
The power consumption is related to the number and type of outputs. The 12 output ECL line-driver version requires the most power at 11 watts.
The PLL automatically goes to the center frequency in the absence of a reference signal and the free-running frequency stability is +- 15 ppm from -40 to +70 Centigrade. The lock-in range is approximately +- 25 ppm. An EIA422A compatible differential lock indicator and an open-collector indicator are provided. An EIA422A input commands the unit to lock or free-run.
RF connector styles are optional. The unit shown in fig. 1 has GPO (Gilbert Engineering Co., Inc.) connectors. Power and control signals are connected by a specially filtered 25 pin D-type connector.
Dimensions may vary depending on the number of outputs and the output frequency and power level. The unit shown features 6 differential ECL line driver outputs and measures 5" x 4.3" x 0.65". The housing is lightweight Aluminum with a tinned nickel plate.
Also see the Blue Tops vibration isolated oscillator.