JPH0239606A - Reception frequency converter - Google Patents

Abstract

PURPOSE:To electrically execute a switching operation by appropriately designing an arithmetic circuit to input the dividing number set value information of a prescaler for obtaining a local oscillation frequency. CONSTITUTION:When the frequency relation between an input signal frequency fS and a local oscillation frequency fL is already known, an arithmetic circuit 4 to input the dividing number set value information of the prescaler for obtaining the local oscillating frequency fL can output a switching control signal 41 accordant with the frequency relation between the input signal frequency fS and the local oscillating frequency fL by appropriately designing the arithmetic circuit 4. A switching circuit 5 receives the switching control signal 41 and switches the connections between two outputs of an image cancel type mixer 2 and two inputs of a 90 deg. hybrid 6 according to the switching control signal 41. Thus, the switching operation for the connections between the two outputs of the image cancel type mixer 2 for outputting a main signal and terminating an image signal and the two inputs of the 90 deg. hybrid 6 can be executed electrically.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a receiving frequency converter used in microwave communication equipment, etc., and in particular to an automatic phase control oscillator (hereinafter abbreviated as APC-O8C) having a prescaler. A receiving frequency converter consisting of an image canceling mixer, a 90' hybrid, and a terminating resistor is involved.

[Conventional technology]

FIG. 2 shows a conventional reception frequency converter. Input terminal 1
The received signal input from the 900 hybrid 6 is mixed down with the signal from the APC-O8C3 in the image canceling mixer 2, and is then transmitted to the output terminal 8 via the switch 9. At this time, the image signal is terminated by the terminating resistor 7.

[Problem to be solved by the invention]

In the conventional reception frequency converter described above, depending on the frequency relationship between the reception signal frequency and the local oscillation frequency, the switch 9 for connecting the two 90° hybrid 60 outputs to the transmission line and the terminating resistor 7 is manually operated. You have to switch from 9.

If you try to configure a reception frequency converter without using the switch 9, depending on the frequency relationship between the reception signal frequency and the local oscillation frequency, the two outputs of the 90°... The only difference is the connection to the resistor.
It is necessary to create two receiving frequency converters that have the same configuration in all other respects. This is because when the signal frequency is higher than the local oscillation frequency and vice versa, the outputs of the main signal and image signal at the two outputs of 90°...IBRID will also be reversed.Conventional reception frequency conversion The only way to deal with this problem is to control a manual switch depending on the frequency relationship, or to provide two circuits with different configurations in advance.90 [Means for solving the problem] Solving the above problems The means provided by the present invention for
an image canceling mixer that receives a received signal and a local oscillation signal and generates @1 and a second signal having a frequency that is the difference between the frequency of the received signal and the frequency of the local oscillation signal; and automatic phase control. an automatic phase control oscillator having a prescaler in the first section and generating the local oscillation signal;
and receives the first and second signals from a second terminal, respectively, and is switched in accordance with a switch control signal applied to a third terminal to transmit the first and second signals to a fourth and second terminal. 90, which outputs one of the signals received from the fourth and fifth terminals from the output terminal and guides the other signal to the terminating resistor;
° A value determined from the relationship between the frequency of the local oscillation signal determined by the frequency division number and the frequency of the received signal. and an arithmetic circuit that generates the switch control signal.

〔Example〕

An embodiment of the present invention is shown in a circuit diagram in FIG.

The receiving frequency converter of this embodiment includes an APC-O8C3 having one prescaler as shown in FIG.
Inside the C-O8C (in order to obtain a predetermined local oscillation frequency, there is an arithmetic circuit 4 that inputs prescaler frequency division number setting value information, an image canceling mixer 2, and a switch circuit 5 consisting of a diode, It consists of a 90° hybrid 6 and terminating resistors 7 and K for terminating the image signal.Here, the switch circuit 5 is controlled by the output of the arithmetic circuit 4.The 90° hybrid 6 has two One of the outputs is connected to the output terminal 8 via a transmission line, and the other is fixedly connected to the terminating resistor 7.

In the embodiment shown in FIG. 1, the circuit configuration is as described above, so if the frequency relationship between the received signal frequency fs and the local oscillation frequency fL is known, the prescaler for obtaining the local oscillation frequency fL can be By appropriately designing the arithmetic circuit 4 which inputs the frequency setting value information, the arithmetic circuit 4 can output the switch control signal 41 according to the frequency relationship between the received signal frequency fs and the local oscillation frequency fL. The switch circuit 5 receives the switch control signal 41 and connects the two outputs of the image canceling mixer 2 with the two inputs of the hybrid 6 (90°) and the hybrid 6 using the switch control signal 4.
Switch according to 1. In this way, in this example,
It is possible to electrically switch the connections between the two outputs of the image canceling mixer 2, which outputs the main signal and terminates the image signal, and the two inputs of the 901' hybrid. Therefore, this embodiment has the advantage that there is no need to change the configuration depending on the frequency relationship between the received signal frequency and the local oscillation frequency, and that a single configuration can correspond to the received signal of any frequency. [Effect of the invention] As is clear from the above, according to the present invention, the switching operation of the connection between the output of the image canceling type middle amplifier and the input of the 90° hybrid is controlled according to the frequency relationship between the received signal frequency and the local oscillation frequency. It is possible to configure a reception frequency converter that is electrically implemented and has a single configuration regardless of the frequency relationship.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a receiving frequency converter according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a conventional receiving frequency converter. 1... Input terminal, 2... Image canceling mixer, 3... Automatic phase control excavator (APC-O8C),
4...Arithmetic circuit, 5...Switch circuit, 6...9
°Hybrid, 7...Terminal resistor, 8...Output terminal, 9...Switch.

Claims (1)

[Scope of Claims] An image cancellation type that receives a received signal and a local oscillation signal and generates first and second signals having a frequency that is the difference between the frequency of the received signal and the frequency of the local oscillation signal. a mixer; an automatic phase control oscillator that has a prescaler in its automatic phase control section and generates the local oscillation signal; a third terminal that receives the first and second signals from first and second terminals, respectively; a switch circuit configured to output the first and second signals from fourth and fifth terminals according to a switch control signal applied to the switch circuit; A 90° hybrid that outputs one signal from the output terminal and leads the other signal to the terminating resistor, calculates the frequency division number of the prescaler, sets the prescaler to the frequency division number, and sets the prescaler to the frequency division number. A receiving frequency converter comprising: an arithmetic circuit that generates the switch control signal having a value determined from a relationship between the determined frequency of the local oscillation signal and the frequency of the received signal.