JPH0352022Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a frequency converter using an image-reject mixer.

[Prior art]

As a mixer that forms the main part of a frequency converter that converts a received high frequency signal into an intermediate frequency signal, an image reject type mixer that does not require a filter to remove an image signal is often used.
FIG. 1 shows a block diagram of a frequency converter using an image-reject mixer. The received high frequency signal is amplified by a high frequency amplifier (RFAMP) 1 and input to the input terminal T ₁ of the mixer 2, while the local oscillation signal is amplified by the local oscillation signal amplifier (LOAMP) 3 and input to the input terminal T ₂ of the mixer 2. . Mixer 2 mixes the high frequency signal with the local oscillation signal and outputs two intermediate frequency signals having different phases from output terminals T ₃ and T ₄ . Further, the hybrid circuit 4 synthesizes these two intermediate frequency signals and extracts and outputs the real component of the signal. By the way, the frequency converters RFAMP1, mixer 2, and LOAMP3 that input high frequency signals above the UHF band
Generally, a hybrid IC is constructed of a distributed constant circuit and has chip components mounted on a dielectric substrate. FIG. 2 shows a specific example of an image-reject mixer constructed from a distributed constant circuit.
0° to 90° hybrid 2 using hybrid circuit
a, single-balanced mixers 2b and 2c using a rattrace circuit, and a 0° to 0° hybrid 2d using a Wilkinson type hybrid circuit.

Note that the terminals T ₁ to _{T 4} in FIG. 2 represent the same terminals as the terminals T ₁ to _{T 4} in FIG. 1, respectively.
As shown in Fig. 2, the image redirect mixer uses a large number of quarter-wavelength lines L to actively utilize the phase difference of the signals, and also has input/output terminals T ₁ to T. The position of ₄ is limited due to the circuit configuration. Therefore, the circuit area of the mixer becomes large, and a frequency converter formed using this mixer ends up requiring a large area.

FIG. 3 is a top view of a conventional frequency converter using the mixer shown in FIG. 2. The case 5 is divided into four parts to accommodate each of the above-mentioned circuits. 1
A is for RFAMP1, 2A is for mixer 2, 3A is for mixer 2.
It is a dielectric substrate on which each circuit of LOAMP 3 is mounted, and 4A is a mounting part of the hybrid circuit 4.
Since the positions of the signal input/output terminals T ₁ to _{T 4} in the mixer are limited, it is necessary to connect each circuit using the connection cable C.

As described above, conventional frequency converters occupy a large area and require processes such as processing and installing connection cables. Furthermore, this connection cable caused deterioration of characteristics. Also generally hybrid
Since IC parts cannot be replaced, they also have the disadvantage that if one circuit breaks down, the entire frequency converter becomes unusable.

[Purpose of invention]

The purpose of the present invention is to eliminate the above-mentioned drawbacks and provide a small and highly reliable frequency converter.

[Structure of the idea]

The frequency converter according to the present invention includes a first case that houses an image-reject mixer, a second case that houses a high-frequency amplifier, a hybrid circuit, and a local oscillation signal amplifier. The bottom surface of the case and the bottom surface of the second case are joined to each other, and the circuit in the first case and the bottom surface of the second case are connected to each other.
It is characterized in that signal connections between the circuits in the cases are made via terminals provided on the bottoms of the connected cases.

〔Example〕

4 and 5 are a top view and a front sectional view, respectively, of a frequency converter according to an embodiment of the present invention. 1B, 2B, 3B, 4B are each RFAMP
The circuit board, mixer board, LOAMP board, and hybrid circuit mounting section are shown. 6 is a connector for high frequency signal input, 7 is a connector for local oscillation signal input, 8 is a connector for inputting a local oscillation signal.
indicates a connector for intermediate frequency signal output; 9, 10
are cases with the same external dimensions. Also
T ₁ -T ₄ represent the same terminals as T ₁ -T ₄ shown in FIG. 1, respectively.

Now, divide the inside of case 9 into three parts, and
The RFAMP board 1B, the LOAMP board 3B, and the hybrid mounting section 4B are stored in the case 10, and the mixer board 2B is stored in the case 10.

Then, the bottom surfaces of case 9 and case 10 are joined together, and terminals T ₁ to _{T 4} such as Teflon insulated terminals are installed in the holes penetrating each bottom surface, and connected to each circuit of case 9 through these terminals T ₁ to T ₄ . Signal connections with the circuit of case 10 are made.

By adopting the above structure, the frequency converter can be significantly downsized. Furthermore, by attaching terminals T ₁ to _{T 4} to the mixer side, which has less flexibility in terminal position, each circuit can be connected over the shortest distance, and the cable of this invention is not required, simplifying the manufacturing process. This also improves reliability. In addition, when mounting chip components on a board, a method is generally used in which the bottom of the case is heated and the components are mounted, but in the present invention, cases 9 and 10 are independent, so small structures mounted above and below can be mounted. Nevertheless, it is possible to heat the bottom surface, and components can be mounted using conventional methods. Furthermore, even in the event of a failure, there is an advantage that only the case containing the failed circuit needs to be replaced.

[Effect of idea]

As explained above, according to the present invention, it is not only possible to provide a small and highly reliable frequency converter, but also to reduce the number of man-hours required for manufacturing the converter.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a frequency converter, FIG. 2 is a circuit diagram of an image redirect mixer according to a specific example, and FIG. 3 is a top view of a frequency converter according to a conventional example. 4 and 5 are a top view and a front sectional view, respectively, of a frequency converter according to an embodiment of the present invention. 1... High frequency amplifier, 2... Image redirect mixer, 3... Local oscillation signal amplifier, 4...
Hybrid circuit, 5, 9, 10... Storage case, 6, 7, 8... Connector, 1A, 1B... High frequency amplifier board, 2A, 2B... Mixer board, 3A, 3B... Local oscillation signal amplifier board for
4A, 4B...Hybrid circuit mounting part, T ₁ ,
T ₂ , T ₃ , T ₄ ...terminals.

Claims (1)

[Claims for Utility Model Registration] A high-frequency amplifier that amplifies a received high-frequency signal, a local oscillation signal amplifier that amplifies a local oscillation signal, an image-reject mixer that mixes the high-frequency signal with the local oscillation signal, and the mixer and a hybrid circuit for extracting a real component from an output signal of the frequency converter, the frequency converter comprising: a first case housing the mixer board;
It has a second case that houses the high frequency amplifier board, the hybrid circuit board, and the local oscillation signal amplifier board, and the bottom face of the first case and the bottom face of the second case are connected to each other. and connect the signal between the circuit in the first case and the circuit in the second case through terminals provided through the bottom surface of each case and each circuit board. A frequency converter characterized by: