The CH1-95 AHM is designed to operate as a source of high-stability, high-accuracy and spectrally pure frequency and timing signals.
The CH1-95 AHM has an autonomous automatic cavity tuning system, which dispenses with the use of another analogous Maser.
The CH1-95 AHM has a built-in self-test system; the unit control and parameters monitoring (including warnings on errors / malfunctions) are performed through touchscreen graphic interface (on-the-spot) and through LAN interface (remotely).
The CH1-95 AHM Applications:
Metrology, time keeping & precision time scaling, frequency reference source, global positioning / navigation satellite systems (GPS / GNSS), deep space tracking, radio astronomy with very long baseline interferometry / array (VLBI / VLBA).
Please note that some compulsory performance parameters values specified for serial production (Frequency Instability and Phase Noise especially) can be improved (tuned up / adjusted) upon a Customer's request.

PERFORMANCE PARAMETERS

Frequency accuracy and stability:

Compulsory values

Typical values

Accuracy (at shipment date)

≤(±)1×10–13

≤(±)5×10–14

Instability sу(2,t) at time interval t
(Allan Deviation):

Compulsory values
(2 Hz bandwidth)

Typical values
(2 Hz bandwidth)

Typical values
(0,5 Hz bandwidth)

1 s

≤1,5×10–13

≤1,2×10–13

≤0,6×10–13

10 s

≤2,5×10–14

≤2,0×10–14

≤1,5×10–14

100 s

≤5,5×10–15

≤4,5×10–15

≤4,5×10–15

1 000 s*

(n/d)

≤1,5×10–15

≤1,5×10–15

10 000 s*

(n/d)

≤1,0×10–15

≤1,0×10–15

100 000 s*

(n/d)

≤3,5×10–16

≤3,5×10–16

1 h*

≤1,5×10–15

≤1,3×10–15

≤1,3×10–15

1 day*

≤5,0×10–16

≤5,0×10–16

≤5,0×10–16

* Specified / measured only under laboratory conditions: during the whole measuring period (not less than 1 day for 1 hour instability measuring; not less than 10 days for 1 day instability measuring) the ambient temperature variation shall be not more than ± 1 °C and with the rate of ambient temperature change ≤0.5°C per hour within 10 to 35 °C operating temperature range at 30 to 80 % operating humidity range; during the whole measuring period the Maser shall be protected against strong magnetic fields and vibration; during the whole measuring period the Maser supply voltage shall be constant, with the surges not more than ± 5 % of the nominal supply voltage value.

Frequency aging (Drift)
(during 24 hours of operation)

≤1×10–15 (at shipment date)
≤5×10–16 (after 6 months of continuous operation)*

* Typically achieved values after a year of continuous unperturbed operation: ≤ 2.0×10–16

Temperature sensitivity

≤1,0×10–15/°C (Typical : ≤0,5× 10–15/°C)

Magnetic field sensitivity

≤5,0×10–15/Gauss

Power source sensitivity

~ 0 (zero within the measurement accuracy)

Frequency settability:

Frequency trim range

1×10–10

Setting resolution

1×10–16

Frequency output signals (sinusoidal)
(2 × 5 MHz, 2 × 10 MHz and 2 × 100 MHz frequency isolated outputs):

Output connectors type

TNC

Amplitude

1 ± 0.2 V RMS (13 ± 2 dBm) into 50 Ohms load

Harmonic distortion

≤–30 dBc (for 5 MHz output)

Non-harmonic distortion (1 Hz - 10 kHz)

≤–100 dBc

SSB phase noise (at 5 MHz, dBc/Hz):

Compulsory values

Typical values

1 Hz

≤–116

≤–120

10 Hz

≤–130

≤–140

100 Hz

≤–140

≤–155

1 kHz

≤–150

≤–160

10 kHz

≤–150

≤–160

100 kHz

≤–150

≤–160

SSB phase noise (at 10 MHz*, dBc/Hz):
*calculated values

Compulsory values

Typical values

1 Hz

≤–110

≤–114

10 Hz

≤–124

≤–134

100 Hz

≤–134

≤–149

1 kHz

≤–144

≤–154

10 kHz

≤–144

≤–154

100 kHz

≤–144

≤–154

SSB phase noise (at 100 MHz*, dBc/Hz):
*calculated values

Compulsory values

Typical values

1 Hz

≤–90

≤–94

10 Hz

≤–104

≤–114

100 Hz

≤–114

≤–129

1 kHz

≤–124

≤–134

10 kHz

≤–124

≤–134

100 kHz

≤–124

≤–134

Timing output signals (pulse)
(2 × 1 Hz (1 PPS) timing isolated outputs, one of the outputs has a correctable timescale):

Output connectors type

TNC

Polarity

Positive

Amplitude (output level is TTL compatible)

2.5 to 5 V Peak (into 50 Ohms load)

Width

10 to 20 μs

Rise time

≤5 ns (typical values: ≤2 ns)

Jitter

≤0.1 ns RMS (typical values: ≤0.02 ns)

Timescale correction range

0 to 1 s

Timescale correction resolution

1 ns

Timing synchronization pulse (synchronization to reference pulse):

Input connector type

TNC

Polarity

Positive

Input impedance

50 Ohms

Time reference

Rising edge

Accuracy (Synchronization error)

≤50 ns (typical values: ≤20 ns)

Amplitude (input level is TTL compatible)

2.5 to 5 V Peak (into 50 Ohms load)

AHM control and monitoring

Touchscreen graphic interface

AHM remote control and monitoring interface

LAN interface control / monitoring functions:
• Unit parameters (check points) control / monitoring;
• Frequency control / correction within 1×10–10 s range and with 1×10–16 s setting resolution;
• Timescale control / correction within 0 to 1s range and with 1 ns correction resolution;
• Check points data transmission, possible errors / malfunctions data transmission.

GENERAL PARAMETERS

Power requirements:

Input voltage:
AC

100 / 120 / 220 V ± 10 %
240 V ± 5 %
47 to 63 Hz

DC (external)*
* At AC power line failure the Maser automatically switches to the external 22 … 30 V DC power supply.

22 to 30 V

Power consumption:

 

AC

≤ 150 VA

DC

≤ 100 W

Environmental requirements:

 

Temperature:

 

Operating

+10 to +35 °C

Storage

–50 to +50 °C

Relative humidity:

 

Operating

up to 80 % at 25 °C

Storage

up to 98 % at 25 °C

Atmospheric pressure:

 

Operating

84 to 106 kPa (630 to 795 mm Hg)

Storage

12 to 106 kPa (90 to 795 mm Hg)

Maser dimensions* (height×width×depth)

955×550×600 mm

* The Maser dimensions are given with an accuracy of ± 3 mm for each (height/width/depth) direction.

Maser weight

100 (± 0.5) kg

Package** dimensions* (height×width×depth)
* The package dimensions are given with an accuracy of ± 50 mm for each (height/width/depth) direction.

1280×780×870 mm

Package** (Maser + Packing Unit) weight

175 (± 5) kg

** The Maser is supplied completed with an Original Packing Unit (plywood box + inner steel transportation frame with two rubber pneumatic shock absorbers). The Original Packing Unit protects the Maser against shocks and strains and provides safety of the Maser during transportation. The Maser shall be transported in its Original Packing Unit only; the Maser transportation without its Original Packing Unit can cause irreparable damage to the Maser. Please keep the Original Packing Unit for the CH1-95 Active Hydrogen Maser within the whole Maser’s lifetime.

Service life

15 years

Standard warranty period

24 months

Extended warranty period (upon a customer's request and at additional charge)

up to 7 years