Telecommunications – Receiver or analog modulated signal frequency converter – Frequency modifying or conversion
Patent
1984-08-29
1986-08-26
Ng, Jin F.
Telecommunications
Receiver or analog modulated signal frequency converter
Frequency modifying or conversion
455328, 333 21R, H04B 126
Patent
active
046087133
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a frequency converter intended to convert the frequency of an input signal of microwave into a lower frequency for use in a converter or the like for sateillite broadcast reception.
BACKGROUND OF THE INVENTION
Generally, a frequency converter for satellite communication wherein reception signals of the SHF band are fed through a waveguide is composed as shown in FIG. 1. That is, it consists of input flange unit 1 through which the SHF signal from the broadcast satellite is first applied, rectangular waveguide unit 2 which is provided in the final end of the rectangular waveguide and possesses a rectangular waveguide-microstrip line converter unit 3, microwave integrated circuit (MIC) 4 which is housed in a shield case 5 and which is responsible for processing of reception signals, and other attached circuits 6. Reference, numeral 7 designates an output terminal, and numeral 8 is an outer case which comprises the rectangular waveguide unit 2 having said rectangular waveguide-microstrip converter unit 3, microwave integrated circuit 4, shield case 5 and attached circuits 6.
In this construction, the SHF signal from the satellite supplied from the input flange unit 1 propagates through the rectangular waveguide unit 2 and enters the microwave integrated circuit 4 by way of rectangular waveguide-microstrip line converter unit 3. In this microwave integrated circuit 4, the signal is amplified and frequency-converted, and is delivered from the output terminal 7 as a signal of intermediate frequency.
As well known, the frequency converter for satellite communication is required to have a large image suppression ratio, small leakage of local oscillation frequency, and low noise index. In this respect, in the conventional constitution as shown in FIG. 1, the image suppression ratio and leakage of local oscillation signal were forced to depend only on the microwave integrated circuit 4, and there was a limit to the circuit design and satisfactory performance could not be obtained.
Another example of a conventional frequency converter is shown in FIG. 2, wherein the same numbers designate to the same parts as in FIG. 1. The converter in FIG. 2 is furnished with a waveguide type filter 9 in the rectangular waveguide unit 2 in order to satisfy the requirements of image suppression ratio and local oscillation signal leakage which were the defects in the conventional example shown in FIG. 1. The other construction is similar to that of FIG. 1.
In this construction, the performances of the image suppression ratio and local oscillation frequency may be sufficiently satisfied, but the insertion loss of said filter 9 exerts adverse effects on the noise index of the frequency converter, which is a serious defect.
DISCLOSURE OF THE INVENTION
The present invention is intended to provide a frequency converter which will satisfy not only the image suppression ratio and leakage prevention of local oscillation signal leakage, but also the noise index characteristic.
More particularly, the present invention provides a frequency converter which is reduced in size while satisfying all of said image suppression ratio, local oscillation signal leakage preventionn and noise index characteristic.
The frequency converter conforming to this invention comprises a circular waveguide unit, a rectangular waveguide comprises an unobstructed circular waveguide unit through one end of which received signals are fed thereto and conveying signals in the TE11 mode; a rectangular waveguide unit having a rectangular waveguide microstrip line converter unit in its output end and conveying signals in the TE10 mode; a circular-rectangular waveguide converter unit connecting the output end of said circular waveguide unit and said rectangular waveguide unit to convert the mode of transmission of signals from the TE11 mode in the circular waveguide unit to a principal transmission mode TE10 in the rectangular waveguide unit; and a microwave integrated circuit extending in the direction of and bei
REFERENCES:
patent: 3230484 (1966-01-01), Lipetz et al.
patent: 3349346 (1967-10-01), Enderby
patent: 3787787 (1974-01-01), Shimada et al.
patent: 4000469 (1976-12-01), McMaster
patent: 4418430 (1983-11-01), Hulderman
patent: 4420756 (1983-12-01), Hamada et al.
Shiomi Yasufumi
Yoshimura Yoshikazu
Matsushita Electric - Industrial Co., Ltd.
Ng Jin F.
LandOfFree
Frequency converter does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Frequency converter, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Frequency converter will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2316270