What is BS EN 60444-8 - Measurement of quartz crystal unit parameters about?  
BS EN 60444-8 is the eighth part of a multi-series that covers the measurement of quartz crystal unit parameters.
BS EN 60444-8 describes test fixtures suitable for leadless surface-mounted quartz crystal units in enclosures as defined in IEC 61837. These fixtures allow the measurement of resonance frequency, resonance resistance, and equivalent electrical circuit parameters L1, C1, and C0 using the measurement techniques specified in IEC 60444-5 and for determining load resonance frequency and load resonance resistance according to IEC TR 60444-4 and IEC 60444-11.
Two test fixtures are described in BS EN 60444-8:
- A fixture using the π-network circuit with electrical values as described in IEC 60444-1 for measurement in transmission mode up to 500 MHz. This fixture includes optional means to add physical load capacitors for the measurement of load resonance parameters up to 30 MHz in accordance with IEC 60444-4. The range of load capacitance is 10 pF or more. Calibration of the measurement system and CL adapter board is explained hereinafter.
- A fixture based on the reflection method, suitable for a frequency range up to 1200 MHz. No provisions for adding a physical load capacitance are anticipated. Load resonance parameters can be measured by using the method of IEC 60444-11.
Who is BS EN 60444-8 - Measurement of quartz crystal unit parameters for? 
BS EN 60444-8 on test fixture for surface mounted quartz crystal units is useful for: 
- Equipment manufacturers
- Electrical engineers and product designers
- Testing houses and laboratories
- Mechanical designers
Why should you use BS EN 60444-8 - Measurement of quartz crystal unit parameters?  
Quartz crystals are available in a broad range of forms and sizes, as well as performance parameters. BS EN 60444-8 focuses on test fixtures applied to leadless surface-mounted quartz crystal units.
BS EN 60444-8 provides users guidance on specifications for fixtures that allows the measurement of (series) resonance frequency, (series) resonance resistance, and equivalent electrical circuit parameters of leadless surface mounted quartz crystal units.
The test fixture and the method are described in BS EN 60444-8 for measuring the resonance frequency, resonance resistance, and equivalent electrical circuit parameters shall be specified in the contract between the crystal unit supplier and the user. The crystal unit requires special consideration as it has no lead wires if load resonance parameters are to be determined.
Measuring equipment described in BS EN 60444-8 will assist you in providing an error-correction feature through internal mathematical processing of measurement values and can eliminate the causes of errors by the connection of the S-parameter equipment with the test fixture.
What’s changed since the last update?
BS EN 60444-8:2017 supersedes BS EN 60444-8:2003, which is withdrawn. BS EN 60444-8:2017 includes some technical changes with respect to BS EN 60444-8:2003. These include: 
- Modification of Clause 1
- Modification of 5.2 
- Modification of 5.3
- Modification of 5.4
- 6.3 Calibration of the reflection measurement system 
