JPH03292015A - Communication equipment - Google Patents

Abstract

PURPOSE:To supply an IF frequency signal to an external detection circuit at all times by providing a frequency conversion section outputting the IF signal of a predetermined frequency to the external detection circuit in response to a change in the local oscillation frequency. CONSTITUTION:An external IF output terminal T1 is connected to the IF input terminal of an external detection circuit 70 and a detection output subjected to digital detection processing by a DSP is inputted to a changeover switch 62 via the route of an AF output terminal and an AF input terminal. The input frequency of the external detection circuit 70 is normally preset and referred to as fd. The oscillating frequency of a 3rd local oscillation circuit is set to the center frequency + or -fd of a 2nd IF filter 32 by operating a changeover switch 63, then the signal received by an antenna is converted into a signal whose frequency is fd and outputted at the external IF output terminal T1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a communication device, and particularly to a communication device for operating an external detection circuit to which a detection circuit is externally attached.

(Prior Art) The number of communication devices such as amateur radios that perform communication in the shortwave radio frequency domain has increased significantly in recent years.

As the number of such communication devices increases, efforts are being made to make them more sophisticated in various fields.

As one of the high-quality tank bottoms, in order to improve sound quality, IF
A digital filter may be used as a filter, or a DSP (Digital Signal Processor) may be used for detection processing.
Attempts have also been made to perform digital processing using ssor).

(Problems to be Solved by the Invention) As mentioned above, in conventional communication devices, external devices using DSP are being upgraded by detection processing, but the input frequency for DSP processing is A value unique to the DSP is determined. However, the conventional configuration in which an input signal and a local frequency signal are mixed and frequency converted to generate a signal in the IFF wave number band has a problem in that it cannot cope with frequency changes.

SUMMARY OF THE INVENTION An object of the present invention is to provide a communication device that can always supply a desired IFF wave number signal to an external detection circuit.

<Means for Solving the Problems> In order to solve the above-mentioned problems, a communication device according to the present invention mixes a radio frequency signal with a first local oscillation signal whose local oscillation frequency is variable by a first mixer section. After converting into an IP band signal, the converted signal is mixed with a second local oscillation signal of variable local frequency by a second mixer unit and converted into an AF band signal,
The communication device for detection includes a frequency converter that outputs an IF multiplied signal of a predetermined constant frequency to an external detection circuit according to a change in the first local frequency.

Further, as this frequency conversion section, a third mixer section that mixes the IF multiplied signal outputted from the first mixer section with a third local oscillation signal having a variable local oscillation frequency, or The local oscillation frequency of the second mixer section may be changed in accordance with the change in the first local oscillation frequency, and the second mixer section may be shared with the frequency conversion section. Furthermore, the timing of the communication device and the external detection circuit is operated based on a clock generated from the same reference clock oscillator.

(Function) In this invention, when an external detection circuit is used in a communication device that converts and detects a radio frequency signal into an F signal and an AF multiplied signal, the mixer circuit According to the change in the local frequency of the local oscillator signal supplied to the external detection circuit, it is possible to supply a signal IF times the desired frequency to the external detection circuit.The conversion to the desired frequency is performed by a mixer circuit provided separately. It is also possible to use a mixer circuit for conversion to an AP signal.In addition, the communication device itself and the external detection circuit can be operated based on the clock from the same reference oscillator. We are also working to improve frequency accuracy.

(Embodiment) FIG. 1 is a block diagram showing the configuration of an embodiment of a communication device according to the present invention.

This embodiment shows an example of receiving an SSB signal,
On the main body side, the signal received by the antenna 10 is processed by a first mixer 21, a first IF filter 31, a second mixer 22, a second IF filter 32, and a third mixer 23. , converted into an IFF wave number signal, and further converted into an audio frequency (AF) signal, and then supplied to the changeover switch 61.

The output of the third mixer 23 passes through the dotted line path of the changeover switch 61, is amplified by the AFF amplifier 90, and then is output to the speaker 1.
At 00, the audio is played back and output. - On the other hand, the output of the second IF filter 32 is further frequency-converted by the fourth mixer 24 and is supplied to the external IFF power terminal.

The first mixer 21, the second mixer 22, the third mixer 23, and the fourth mixer 24 are the first local oscillator circuit 41, the second local oscillator circuit 42, and the third local oscillator circuit 4, respectively.
Upon receiving the local oscillator signals from the third and fourth local oscillator circuits 44,
The local oscillator frequencies of these first to fourth local oscillator circuits 41 to 44, which perform mixing processing with each input signal, are controlled based on a control signal from the frequency determination data generator V180.
Each is adjusted based on signals from L circuits 51 to 54.

The frequency setting data generating means 80 is a reception frequency variable knob], 1. By operating the O1 band variable knob 120, each of the PLI circuits 51 to 54 is arbitrarily adjusted.

The basic timing of the above processing (the basic frequency of phase comparison of each PLL circuit) is determined based on the reference clock from the reference oscillator 130. By operating the band variable knob 110, the oscillation frequencies of the first to fourth local oscillator circuits 41 to 44 are adjusted, and the band is adjusted. For example, the second local oscillator circuit 4
2 and the local oscillator frequency of the third local oscillator circuit 43 change by the same amount, the center frequencies of the first filter 31 and the second IF filter 32 shift, so that the passband of each IF filter changes. If they are equal, the overall passband will be narrower.

On the other hand, in order to achieve high sound quality, when using the external detection circuit 70 set as an option using, for example, a DSP, the changeover switches 61 to C)3 are switched from the dotted line position to the solid line position, and the fourth The output signal from mixer 24 is output to external IF output terminal T.

is supplied to

The external IF output terminal T is connected to the IP input terminal of the external detection circuit 70, and performs digital detection processing by a DSP, for example, PSN (Phase Shift Network).
) The processed detection output is input to the changeover switch 62 via the AF output terminal and the AF input terminal. External detection circuit 87
0 is the reference oscillator 130 via the external reference output terminal T2.
It operates with a reference clock supplied from

Since the selector switch 62 is in the solid line position when the external detection circuit 70 is used, the audio output from the external detection circuit 70 is amplified by the AP amplifier 70 and sent to the speaker 100.
to drive.

At this time, the input frequency of the external detection circuit 70 is usually determined in advance, and this frequency is set as fd. fd is set to 36 KHz, for example.

When the oscillation frequency of the third local oscillation circuit is adjusted to the center frequency ±fd of the second IF filter 32 by operating the changeover switch 63, the signal received by the antenna is output to the external IF output terminal T. It will be converted into a signal of frequency fd and output.

When the band variable knob 120 is operated, the oscillation frequency of each local oscillator circuit changes as described above, but if this continues, the center frequency of the signal appearing at the external IP output terminal T will deviate from fd. Therefore, the oscillation frequency of the local oscillation circuit 44 of the noodles 4 is adjusted so that the deviation becomes zero.

The fourth local oscillator circuit 44 may be provided on the 5 main body side or may be provided on the external detection circuit side.

FIG. 2 shows a block diagram of another embodiment of the communication device according to the invention.

In the embodiment shown in FIG. 2, the function of adjusting the output frequency to the external detection circuit 70 is provided by the fourth mixer 24 and the fourth local oscillator circuit!
Since this is achieved by controlling @44 and the PLL circuit 53, the hardware configuration is simplified9. That is, in this embodiment, when the external detection circuit 70 is not used, the frequency setting data generation means 80 When performing normal frequency conversion such that the output of the third mixer 23 becomes an AF signal by controlling the external detection circuit 70, the frequency setting data generation means 80 is controlled to Set the output frequency to fd above. Switching when such an external detection circuit 70 is used is performed by a changeover switch 63.

In the embodiments described above, it goes without saying that a clock obtained by frequency-dividing the oscillation output from the reference oscillator 130 can be used, and its setting location is also arbitrary.

(Effects of the Invention) As explained above, when the communication device according to the present invention uses an external detection circuit that performs special processing for the purpose of improving quality, etc., the communication device performs variable reception band adjustment on the main body side. Even if the external detection circuit is in use, it is possible to always output a signal IF times the desired center frequency required by the external detection circuit to the external detection circuit. Also, since the internal detection circuit on the main body side can change its local frequency, the external detection circuit has the desired center frequency I/O.
Since the F signal can be output, there is no need to separately provide a special circuit.

Furthermore, since the clock for operating the external detection circuit shares the reference clock from the reference oscillator provided on the main unit, the external detection circuit is also controlled with the same frequency accuracy as the main unit. Variable knob, 130...Reference oscillator.

Claims (4)

[Claims] (1) The first mixer unit mixes the radio frequency signal with the first local frequency variable local oscillator signal and converts it into an IF band signal, and then the converted signal is used as the local oscillator signal by the second mixer unit. In a communication device that mixes a frequency-variable second local oscillator signal, converts it into an AF band signal, and detects the signal, externally detects an IF signal of a predetermined constant frequency in response to a change in the first local oscillator frequency. A communication device comprising a frequency converter that outputs to a circuit. (2) The frequency conversion section is a third mixer section that mixes the IF signal output from the first mixer section with a third local oscillation signal having a variable local oscillation frequency. 1. The communication device according to 1. (3) The communication device according to claim 1, wherein the local oscillation frequency of the second mixer section is changed in accordance with a change in the first local oscillation frequency and is shared with the frequency conversion section. . (4) The communication device according to claim 1, wherein the communication device and the external detection circuit perform timing operations based on a clock generated from the same reference clock oscillator.