In order to obtain fine contacts over the crystal unit, it is necessary to apply a thin layer of metal electrodes on its surface. The structure of the thin metal film formed by evaporation and ...condensation under the vacuum depends on many parameters and therefore it is very important to define the terms of steaming. This paper describes a method for achieving a good structure of thin metal films in high quality crystal units with SC cuts, which are designed for high quality OCXO oscillators.
Crystal oscillators and filters are still very important devices in modern telecommunication and measurement equipment. Quartz crystal units are basic elements for those oscillators and filters, due ...to their extremely stable resonant frequency and Q-factor. Matched crystal filters are consisted of filter sections with the same phase characteristics. In this paper the design and realization of a new type of matched filters with quartz crystal units is described.
A new crystal filter F 106 Dujkovic, D. M.; Nesic, S. D.; Grubisic, L. ...
2012 20th Telecommunications Forum (TELFOR),
2012-Nov.
Conference Proceeding
In modern communications, it is of great importance to implement quality modules for signal transmission, transfer and reception. One of the most important components of those modules is crystal ...filter. This is especially true for digital communications. In this paper, we propose antenna-filter F 106, suitable for high frequencies. This new filter is based on crystal units. We describe its design and present the final product.
U radu je opisan postupak projektovanja i izrade kristalnih filtara na bazi kristala kvarca, koji rade na učestanosti od 70 MHz, a koji imaju kontrolisanu faznu karakteristiku. Novi tip kristalnog ...filtra propusnika učestanosti sa centralnom frekvencijom 70MHz projektovan je prema zahtevima korisnika opisanim u listi tehničkih podataka. Ovakvi filtra imaju razne namene u vojnim i civilnim telekomunikacijama.
Quartz crystal units (CUs) are the most popular oscillating components in high-quality crystal filters and oscillators, due to their electrical and mechanical characteristics. This paper considers ...design and realization of high quality 76.8375 MHz crystal filter based on third overtone quartz crystal units. In addition to the basic parameters, this filter also meets the special operational conditions of the environment (clime and mechanical conditions). Filter design and requested specifications are further explained as well as the resulting transfer function of the 76.8375 MHz filter.
New stop band 48 MHz crystal filter Dujkovic, Dragi M.; Nesic, Snezana Dedic; Grubisic, Lenkica ...
2021 29th Telecommunications Forum (TELFOR),
2021-Nov.-23
Conference Proceeding
Band stop filter or band-rejection filter, with narrow attenuation characteristic is described in this paper. These filters do not pass signals within the cutoff frequencies. Аt the specific request ...of the customer, a crystal filter was realized, which operates at a frequency of 48MHz. When measuring the non-linearities of power amplifiers, a very narrow notch filter can be very useful to avoid the carrier frequency. Use of the filter may ensure that the maximum input power of a spectrum analyser used to detect spurious content will not be exceeded. Such filters are used in modern telecommunications for civilian and military purposes.
Paper describes a new technological process of suppression of spurious in fifth overtone crystal units (CU) AT cut type. The development of new crystal filter is based on micro-miniature quartz ...crystal units, because of the reduced size of new devices in telecommunications. One of the most important characteristics of CU quality is possibility of suppression of spurious resonances, and this method provides it with minimal technological changes with very small degrading of CU's dynamics.
This paper describes a new technological process of chemical polishing of SC cut crystal units. Due to the absence of a deformed layer on the surface of chemically polished units, that is always ...present in mechanically polished units, and the possibility to inspect crystal defects during abrasion, it is possible to select the defect-free units. Chemically polished units are characterized by improved mechanical durability compared to mechanically polished ones.
In modern communications, particularly digital one, it is very important to implement quality modules for receiver, transmitter and/or repeater units. One of the most significant components of those ...modules are crystal filters. This paper presents a computer simulation of crystal filter composed by four crystal units. By changing the filter parameters it is possible to tune the pass-band and stop-band filter attenuation. Using computer simulation we can select the best filter parameters assuring the quality of the manufacturing process of the appropriate filter.
High quality crystal filter which operates at 50 MHz has been realized. The filter with bandwidth of 15 kHz, and special requirements regarding the electrical and environmental characteristics, is ...designed by using the transformation techniques applied on the cascade of lattice sections. Filter realization was performed at the Institute Mihailo Pupin, Belgrade, in cooperation with the Faculty of Electrical Engineering, University of Belgrade.
