Rubidium Clock Quick Start Guide

BRIDZA

Table of Contents

• Unboxing Checklist
• Power-On Procedure
• Output Signal Verification
• Serial Connection & SCPI Commands
• GNSS Disciplined Mode (STW-FS Series)
• Troubleshooting

1. Unboxing Checklist

Standard Package Contents

Pre-Power Inspection

• [ ] Verify model number matches order (e.g., STW-Rb05, STW-Rb10)
• [ ] Check serial number label on rear panel
• [ ] Inspect all connectors for bent pins or damage
• [ ] Confirm input voltage selector (115V/230V) if applicable
• [ ] Record serial number for warranty registration

2. Power-On Procedure

2.1 Power Sequence Requirements

2.2 Power-On Timing Sequence

T+0s: Power applied
T+0-2s: Internal circuits initialize
T+2-5s: Rb lamp ignition begins
T+5-30s: Lamp warm-up phase
T+30s-5min: Crystal oven stabilization
T+5-15min: Rb transition optimization
T+15-30min: Full frequency lock achieved

2.3 Pre-Warm-Up Steps

• Connect Power: Attach power cable securely
• Verify Ground: Ensure chassis ground is connected
• Check Voltage: Use multimeter to verify DC supply
• Power On: Toggle power switch to ON position

2.4 Warm-Up Time Requirements

Important: Allow minimum 15-minute warm-up before measuring frequency stability. Full specifications achieved after 30 minutes.

3. Output Signal Verification

3.1 Standard Output Configuration

3.2 Verification with Frequency Counter

Equipment Required: Frequency counter with ≥10 digit resolution

Procedure:

• Connect 10MHz output to frequency counter
• Set counter to 1-second gate time
• Record frequency reading after 10 consecutive measurements
• Average reading should be: 10,000,000.000 Hz ± specification

Pass Criteria:

• Frequency accuracy within ±5×10⁻¹¹ after 24-hour warm-up
• Standard deviation < 1×10⁻¹¹ over 100 samples

3.3 Verification with Spectrum Analyzer

Equipment Required: Spectrum analyzer with 100kHz-50MHz range

Procedure:

• Set span: 100kHz centered on 10MHz
• Set RBW: 1kHz
• Set VBW: 100Hz
• Enable marker function
• Verify carrier at 10MHz with expected amplitude

Expected Results:

• Harmonic suppression: >40 dBc
• Spurious signals: <-60 dBc
• Phase noise: Meets specification sheet values

3.4 1PPS Verification

Procedure:

• Connect 1PPS output to oscilloscope
• Set trigger to 50% threshold on rising edge
• Verify pulse width: 1μs to 100ms (configurable)
• Measure pulse amplitude: Should match specification
• Verify duty cycle: 50% ±5% (for configurable units)

4. Serial Connection & SCPI Commands

4.1 Physical Connection

Serial Parameters:

Cable Requirements:

• PC to unit: Standard RS232 cable (NULL modem not required)
• USB connection: Use provided USB-to-Serial adapter

4.2 SCPI Command Overview

All BRIDZA rubidium clocks support standard SCPI-1994 commands.

Identification Commands

*IDN? // Returns: BRIDZA,,,
*OPT? // Returns installed options
*VER? // Returns firmware version

Frequency Control Commands

:FREQ:REF:SOURce RBO | EXT | GNSS // Select reference source
:FREQ:REF? // Query current reference
:FREQ:TRACK ON | OFF // Enable frequency tracking

Output Commands

:OUTP:CH1 ON | OFF // Enable/disable 10MHz output
:OUTP:CH2 ON | OFF // Enable/disable 5MHz output
:OUTP:CH3 ON | OFF // Enable/disable 1PPS output
:OUTP? // Query all outputs

Status Commands

:STAT:OPERation? // Query operation status
:STAT:QUEStion? // Query question status
:DIAG:POWer? // Query power supply voltages
:DIAG:REFerence? // Query reference lock status

Example Session

*IDN?
> BRIDZA,STW-Rb10,SN-RB20240001,v2.3.1

:FREQ:REF?
> RBO

:STAT:OPERation?
> 256 // Bit 8 = 1 indicates locked

:OUTP:CH1 ON
> OK

4.3 Python Example

import serial
import time

class BRIDZA_Rubidium:
 def __init__(self, port='/dev/ttyUSB0', baud=9600):
 self.serial = serial.Serial(port, baud, timeout=1)
 
 def command(self, cmd):
 self.serial.write(f"{cmd}\n".encode())
 time.sleep(0.1)
 return self.serial.readline().decode().strip()
 
 def get_identity(self):
 return self.command('*IDN?')
 
 def get_lock_status(self):
 status = int(self.command(':STAT:OPER?'))
 return bool(status & 256) # Lock bit
 
 def get_frequency_error(self):
 return float(self.command(':FREQ:ERROR?'))
 
 def close(self):
 self.serial.close()

# Usage
clock = BRIDZA_Rubidium('/dev/ttyUSB0')
print(clock.get_identity())
print(f"Locked: {clock.get_lock_status()}")
clock.close()

5. GNSS Disciplined Mode (STW-FS Series)

5.1 GNSS Antenna Installation

Antenna Requirements:

Installation Guidelines:

• Mount antenna with clear sky view (elevation >45°)
• Avoid proximity to transmitting antennas
• Minimum 3m separation from GPS interference sources
• Use quality coaxial cable (RG-213 or better) <20m

5.2 GNSS Configuration

:GNSS:MODE GPS | GLONASS | GALILEO | BEIDOU // Select GNSS constellation
:GNSS:MODE? // Query current mode
:GNSS:SATellites? // Query visible satellites
:GNSS:HOLDover:TIME? // Query holdover duration
:GNSS:DISCipline:RATE? // Query discipline rate

5.3 Discipline Parameters

5.4 Discipline Status Monitoring

:GNSS:STATus? // Returns: TRACKING, HOLD, UNLOCK
:GNSS:HDOP? // Returns: Horizontal DOP (should be <3)
:GNSS:POSITION? // Returns: Lat, Lon, Alt
:GNSS:ANTenna:VOLTage? // Returns: Antenna voltage (should be 5V ±0.5V)

6. Troubleshooting

6.1 No Output Signal

6.2 Frequency Offset

6.3 1PPS Not Present or Irregular

6.4 GNSS Not Locking (STW-FS Series)

6.5 Communication Failure

Technical Support

For additional assistance:

• Email: [email protected]
• Documentation: https://rf.bridza.com/downloads
• Knowledge Base: https://rf.bridza.com/support

Document Version: 1.0 | Last Updated: 2025