JP2512528B2 - Receiver with synthesizer tuner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a receiver equipped with a synthesizer tuner such as a synthesizer type AM / FM receiver, and in particular, an AM inter-station frequency without adding an operation key. For receivers that can be changed and set.

[Prior Art] In a receiver having a synthesizer tuner, for example, a synthesizer type AM / FM receiver, if a reception frequency is automatically swept, a broadcasting station within the reception area can be automatically selected. In this case, the sweep frequency step is usually selected as the inter-station frequency.

If this is not the case, it may take a long time to tune in, or the target broadcast station may be skipped and reception may become impossible.

As is well known, the frequency between stations is 10KHz in the US and Canada for AM receivers and 9KH in other regions including Japan.
Selected as z.

In the case of FM receivers, the inter-station frequency is selected to be 200 KHz in the United States and Canada and 100 KHz steps in other regions.

Further, in the case of the FM receiver, the de-emphasis characteristic differs depending on the inter-station frequency in addition to the inter-station frequency.

When the frequency between stations is 200 KHz, 75 μsec (about 13.3 KH
z), but the frequency between stations is 100KH
In the case of z, it is set to about 50 μsec (about 20.0 KHz).

[Problems to be Solved by the Invention] With the recent development of transportation means, cross-border traffic is becoming more and more prominent. With such human interaction, broadcast receiving devices such as AM / FM receivers. However, I often come and go while carrying this.

Especially in Japan and the United States, where economic ties are deep,
There is a lively exchange between businessmen and tourists.

In such a case, for example, in Japan, when the AM / FM receiver's AM inter-station frequency is set to 9 KHz and it goes to the United States, if the AM inter-station frequency is left as it is and it is automatically swept, the broadcasting station that can be originally received in the US It is also skipped and it becomes impossible to receive. This is because the AM inter-station frequency differs between Japan and the United States, as described above.

On the contrary, when using the AM / FM receiver whose AM inter-station frequency was set to 10 KHz to receive the broadcasting station in the United States in Japan, the same problem as described above was caused. Will be done.

In order to eliminate such adverse effects, in the past, a manual switch for switching the AM inter-station frequency was incorporated into the set,
When the frequency between AM stations is different, this manual switch was operated to match the frequency between AM stations in the receiving area.

However, the provision of such a switch results in an increase in the cost of the device.

On the other hand, the synthesizer AM / FM receiver has a built-in microcomputer for controlling the synthesizer tuner as described above. In that case, if the microcomputer and the manual switch are installed in a set in a state where they are separated from each other, that line will act as an antenna line, which will cause unwanted radiation to leak to the outside or external noise. May pick up. This is because this may cause a problem that the S / N of the received signal is deteriorated.

In addition, when receiving an FM broadcast, the de-emphasis characteristics differ depending on the difference in the frequency between FM stations, so the sound quality deteriorates unless the de-emphasis characteristics are changed appropriately.

In other words, when an FM broadcast with a de-emphasis characteristic of 50 μsec is being received, if you listen to the FM broadcast within the reception area where the FM inter-station frequency is 200 KHz with the de-emphasis characteristic as it is, only the high frequencies will be emphasized. The sound quality is very offensive.

Also in this case, if a dedicated switch is provided as in the case of the inter-station frequency, the same problem as described above will be caused.

In view of the above, the present invention has proposed a receiver having a synthesizer tuner capable of changing the inter-station frequency or the de-emphasis characteristic without adding a key, as a solution to such a conventional problem. is there.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the present invention,
A tuning operation unit consisting of multiple keys for selecting the broadcasting station to be received, inter-station frequency setting means that can set the sweeping inter-station frequency to different values, and de-emphasis characteristics to different values. Between the de-emphasis circuit that can be set and when two keys of the first combination of the plurality of keys are operated simultaneously and when two keys of the second combination are operated simultaneously The control means controls the inter-station frequency set by the frequency setting means or the de-emphasis characteristic set by the de-emphasis circuit so as to have different values.

[Operation] The function to be automatically set is the inter-station frequency or de-emphasis characteristic. For AM receivers, it is the AM inter-station frequency, and for FM receivers, it is the FM inter-station frequency.

In the AM / FM receiver, the frequencies between both stations are changed.

In addition to this, in the embodiment, the de-emphasis characteristic of FM is also changed.

Such a change processing operation is determined by whether or not the two specified keys are simultaneously operated.

In the embodiment, when the memory key M and the up key U (first combination key) for increasing the sweep frequency are simultaneously operated, the AM inter-station frequency is set to 9 KHz and the de-emphasis characteristic is set to 50 μsec.

On the other hand, when the memory key M and the down key D (second combination key) for lowering the sweep frequency are simultaneously operated, the AM inter-station frequency is set to 10 KHz and the de-emphasis characteristic is set to 75 μsec. .

This makes it possible to achieve the above-mentioned automatic change process by skillfully utilizing the existing key.

In addition to the above, the frequency between FM stations can be changed at the same time.

[Example] Next, an example of a receiver having a synthesizer tuner according to the present invention will be described with reference to the synthesizer system as described above.
The case of application to an AM / FM receiver will be described in detail with reference to FIG.

In this example, the de-emphasis characteristic of FM can be changed at the same time as the frequency between AM stations.

FIG. 1 is a system diagram showing an example of a synthesizer type AM / FM receiver according to the present invention, where 10 is an AM receiver and 70 is
FM receiver, 20 is a synthesizer tuner commonly provided for each.

In the AM receiver 10, 1 is a high frequency amplifier circuit and 2 is a mixer. A synthesizer tuner 20 having a PLL configuration is connected to the mixer 2.

3 is an intermediate frequency amplifier circuit, 4 is an AM detector, 5 is a low frequency amplifier, and 6 is a speaker.

 The FM receiver 70 is similarly configured.

Reference numeral 71 is a high-frequency amplifier circuit forming the front end, 72 is a mixer, 73 is an intermediate-frequency amplifier circuit, and 74 is an FM detector.
The FM output is supplied to the low frequency amplifier 5 after its frequency characteristic is limited by the de-emphasis circuit 90.

 Details of the de-emphasis circuit 90 will be described later.

The synthesizer tuner 20 described above has a PLL configuration. Therefore, it has a fixed reference oscillator 21 and variable oscillators 22 and 26.

In this example, although the variable oscillators 22 and 26 have a shared configuration, the frequency bands of the variable oscillators 22 and 26 are significantly different, and therefore a dedicated variable oscillator is used. 22 is a variable oscillator for AM, 26 is FM
Is a variable oscillator for.

Then, either one of the oscillation outputs is selected according to the band switching.

The outputs of the variable oscillators 22 and 26 are supplied to the mixers 2 and 72 as their local oscillation signals, and the programmable dividers are
23, the divider output is compared with the reference oscillation output of the reference oscillator 21 in the phase comparator 24, and the phase comparison output is passed through the low pass filter 25 and the variable oscillator 2
It is supplied as a voltage control signal for 2,26.

The programmable divider 23 is supplied with a command signal necessary for receiving a predetermined broadcasting station from the microcomputer 30 which controls various controls of the AM / FM receiver, and the programmable divider 23 of the programmable divider 23 is supplied in accordance with the command signal. Programmable values are controlled.

Now, the AM receiver 10 and the signal detectors 40 and 80 provided in each of the FM receiver 70 both amplify and detect-switch the high frequency signal changed to the intermediate frequency when the broadcast station is received, It outputs a signal related to the presence or absence of a broadcasting station.

The de-emphasis circuit 90 provided in the FM receiver 70 is
It is configured as an RC circuit as shown, and has a resistor R and capacitors C1 and C2 connected in parallel.

A control transistor Q is connected in series with one of the capacitors C2. The control transistor Q is controlled by a control signal from the microcomputer 30.

When receiving FM broadcasts in the US, etc., the time constant of the de-emphasis circuit 90 must be changed to 75 μsec, which is larger than that in Japan. In that case, the control signal turns on the control transistor Q. It is controlled by the state. In this case, the capacitors C1 and C2 are connected in parallel, and the time constant increases.

Therefore, the time constant R · C1 is 50 μsec, and the time constant R · (C1
Each value is selected so that + C2) is 75 μsec.

In the microcomputer 30, a process control program for executing a corresponding change process when two specific keys are simultaneously operated is built in.

As a specific key, in this example, among the keys provided in the tuning operation unit 35 as shown in FIG. 3, the memory key M
And the up key U (first combination) and the memory key M and the down key D (second combination). P (Po to P4) indicates a preset key.

Now, in this example, in addition to the AM inter-station frequency as described above,
The constant of the de-emphasis circuit 90 provided in the FM receiver 70 is also automatically changed. This inter-station frequency setting and constant setting processing of the de-emphasis circuit 90 is executed at the same time when the power is turned on, and is executed regardless of whether the reception band is the AM / FM band.

An example of the control program will be described with reference to the control flowchart of FIG.

In the example described below, the AM inter-station frequency is 9 KHz.
Although both 10 kHz and 10 kHz are illustrated, the setting of the AM inter-station frequency is merely an example.

First, the processing program starts when the first power is turned on. In this example, when the power is turned on, the FM de-emphasis characteristic is automatically set to 75 μsec and the AM inter-station frequency is automatically set to 10 KHz (steps 41 and 4).
2).

The initial setting process may be set in advance at the stage of product shipment from the factory. For example, in connection with the microcomputer 30, the signal level given to the specific port may be preset. The default contents may be selected depending on the product destination country.

When the initial setting process of the FM de-emphasis characteristics and the AM inter-station frequency is completed, the operation contents of the keys are next read from the key operation unit (not shown) of the apparatus main body and the tuning operation unit 35 (step 43). ).

After that, the operation state of the memory key M is checked, and when this key is not operated and when another key is operated, a series of processes corresponding to it (broadcast station reception process, etc.)
Is performed (steps 44 and 45).

When the memory key M is operated, it is checked which one of the specified keys other than the memory key M is operated at the same time (step 46).

If this is not the relationship between the first combination keys M and U, then it is checked whether there is a relationship between the second combination keys M and D, and if it is not this combination, then a transition is made to a series of preset write modes. (Steps 47, 48).

That is, when the memory key M is operated, it is considered that at least the channel preset mode or the above-described inter-station frequency change mode is set.

As a result of the key discrimination, when it is confirmed that it is the first combination key M, U, the FM de-emphasis characteristic is 50 μse.
At the same time as changing to c, the AM inter-station frequency is changed to 9 KHz (steps 51 and 52).

On the other hand, when the key is the second combination key M, D, the de-emphasis characteristic is changed to FM75 μsec and the AM inter-station frequency is changed to 10 KHz (steps 41 and 42). However, in this example, since the de-emphasis characteristics and the inter-station frequency have already been initialized, the contents are not changed.

As for the inter-station frequency, in addition to the case of AM, the inter-station frequency of FM can be changed at the same time. That is, the first combination key
When M and U are operated, the frequency between FM stations is set to 100KHz. In the case of the second combination keys M and D, the inter-station frequency is set to 200 KHz.

In the case of an AM receiver, only the AM inter-station frequency needs to be changed.

In the case of FM receiver, in addition to the de-emphasis characteristics,
The frequency between FM stations is changed.

[Effects of the Invention] As described above, according to the configuration of the present invention, when two specified keys are operated simultaneously, a specific change process (inter-station frequency) accompanying the specified key operation is performed. Change processing, etc.) can be realized.

Therefore, according to the present invention, by making good use of the existing operation keys, a predetermined change process can be performed without adding any keys.

As a result, since it is not necessary to provide a manual switch used for changing the frequency between stations, it is possible to easily reduce the cost of the device.

Of course, by providing this manual switch, there is no risk of unnecessary radiation leaking to the outside or inadvertently picking up external noise, so that the S / N of the received signal can be improved.

[Brief description of drawings]

FIG. 1 is a system diagram of an essential part showing an example of a receiver having a synthesizer tuner according to the present invention, and FIG. 2 is a control flow chart for explaining automatic setting processing of inter-station frequency and changing processing of de-emphasis characteristic. FIG. 3 and FIG. 3 are plan views showing an example of the tuning operation unit. 2,72 …… Mixer 3,73 …… Intermediate frequency amplification circuit 4,74 …… Detector 10 …… AM receiver 20 …… Synthesizer tuner 22,26 …… Variable oscillator 30 …… Microcomputer 40,80 …… Signal detector 90: De-emphasis circuit Q: Control transistor P: Preset key M: Memory key U: Up key D: Down key

Claims (1)

(57) [Claims] 1. A tuning operation section comprising a plurality of keys for selecting a broadcasting station to be received, an inter-station frequency setting means capable of setting sweeping inter-station frequencies to different values, and de-emphasis. A de-emphasis circuit that can set the characteristics to different values, and when the two keys of the first combination among the plurality of keys are operated simultaneously and the two keys of the second combination are operated simultaneously. And a control means for controlling the inter-station frequency set by the inter-station frequency setting means or the de-emphasis characteristic set by the de-emphasis circuit so as to have different values. Receiving machine.