Telecommunications – Transmitter and receiver at separate stations – Having measuring – testing – or monitoring of system or part
Patent
1995-02-10
1997-08-19
Eisenzopf, Reinhard J.
Telecommunications
Transmitter and receiver at separate stations
Having measuring, testing, or monitoring of system or part
455115, 4552261, 331176, 331158, H04B 1700
Patent
active
056598840
ABSTRACT:
A method and an apparatus for compensating for aging and temperature of the crystal in a crystal oscillator. An RF signal which is transmitted by a mobile telephone switching office (MTSO) (108) and received by the antenna (118). The signal transmitted by the MTSO (108) serves as an external reference. A crystal-controlled main oscillator/time base generator (134) provides a local reference frequency to the converters (120) and provides a time base signal to a counter (136). A controller (112) reads an aging correction value from a memory and provides a frequency control signal to the main oscillator (134). The converters (120) convert the received RF signal to an IF frequency. A limiter (122) provides a limited IF signal to the counter (136). Counter (136) counts the number of cycles of the limited IF signal that appear in a cycle of the time base signal. A controller (112) compares this measured count to a reference count and the count error is determined. The count error is compared to an allowable count error. If the count error is excessive then the controller (112) adjusts the frequency control signal provided to the main oscillator (134) so as to change the frequency of the main oscillator (134). Once the controller (112) has shifted the frequency so that the count error is not excessive then the controller (112) stores the new aging correction value. The measured count is therefore depends upon the frequency of the main oscillator (134) and the frequency of the received signal. This process automatically compensates for the frequency of the main oscillator (134) and, therefore, for aging of the crystal. The frequency of oscillation of the main oscillator (134) is therefore as accurate as the external reference, typically the highly accurate MTSO (108). A high precision oscillator (134) has thus been obtained using an external reference (MTSO 108) and an aging correction value.
REFERENCES:
patent: 4922212 (1990-05-01), Roberts et al.
patent: 5201063 (1993-04-01), Tam et al.
patent: 5392005 (1995-02-01), Bortolini et al.
patent: 5423070 (1995-06-01), Vaisanen et al.
patent: 5477194 (1995-12-01), Nakakura
Methot, Francois, "Crystal Oscillator Compensation in a DDS/PLL Application", RF Design Awards, pp.88-89, Jan. 1995.
Daughtry, Jr. Earl A.
Quire Christopher S.
Ruff Mark A.
Stone Richard M.
Eisenzopf Reinhard J.
Matsushita Communication Industrial Corp. of America
Sobutka Philip J.
LandOfFree
System with automatic compensation for aging and temperature of does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System with automatic compensation for aging and temperature of , we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System with automatic compensation for aging and temperature of will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1114730