When the filters are inserted at the test adapter, the insertion loss is the difference between the minimum attenuation value of the filter and the reference point.Д«) The passband range between two frequencies (f1, f2), where the attenuation should be equal to or higher than a specific value. The resulting attenuation value is the corresponding reference point 0. Definition of electrical parametersДЄ) Insertion loss In order to measure the insertion loss, the test adapter is short circuited and the imaginary impedances are compensated at the corresponding centre frequency. A drawback is the higher temperature response of LC-filters because of the temperature dependent elements coils and capacitors. Another advantage is the lower spurious response of a LC-filter. These filters provide a much wider passband with nearly the same shape-factor as crystal filters. LC-filters are a combination of coils and capacitors instead of using a crystal. The linearity and the temperature characteristic of the slope is determined by the electrical parameters as well as by the temperature characteristics of the crystal. Within a certain frequency range, crystal discriminators produce a DC-voltage proportional to the input frequency. Crystal discriminatorsД¬urrently KVG produces crystal discriminators in the frequency range of 1 MHz to 35 MHz (priority from 9 MHz to 25 MHz) for linear FM-demodulation and for measurement applications. The most important characteristics of these filters are low insertion loss and good intermodulation characteristics. Antenna filtersДЄntenna filters, used as preselection or as front-end filters in the VHF-range, suppress unwanted signals. By several transfer functions (Gauss 6 dB, Gauss 12 dB, EQR) between linear phase and selection filters, better selectivity can be achieved without essentially changing the group delay in the pass band range. However, these linear phase filters (Gaussian or Bessel characteristic) have low selection characteristics. In order to get a low distortion transmission of signals and pulses (digital signals), crystal filters with a linear phase response or low group delay distortion are necessary. Some of the filters give the option of internal matching networks. Depending on the selection in the stop-band range and the ripple in the pass-band range the filter design can be chosen between Chebyshev-design and Butterworth design (theoretical ripple 0 dB). The crystal filters supplied by KVG are mainly band-pass filters with Chebyshev-characteristic (theoretical ripple 0.1 dB). Monolithic crystal filters are mostly used in IF -stages of fixed and mobile radios. Bandwidth, stopband attenuation, ripple, group delay, intermodulation etc.Дepending on the applied technology it is common to divide filters into five main types:ДЄ very similar product is a crystal disriminator, which can be used for FM-demodulation and for measurement applications.Most of the applications imply an exact specification of the filter.

In house filter design and crystal manufacturing combined with new technologies like HFF-crystals gives a maximum of flexibility to the customer.

KVG provides a wide spectrum of standard and custom specific filters for telecommunication, navigation, avionics and precise measurement for filters in the frequency range of 1 MHz to 200 MHz.

Crystal filters Filters / Discriminators Applications for Filters/ Discriminators

8 khz bandwidth crystal filter design