JPH088468B2 - 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 that case, the step of the sweep frequency 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 inter-station frequency is 10 KHz in the US and Canada for AM receivers and 9 KHz in other regions including Japan.
Has been selected.

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.

If the frequency between stations is 200 KHz, 75 μsec (role 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 of being separated from each other, that line will act as an antenna line, which may cause unnecessary radiation to leak to the outside, May pick up noise. 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.

That is, when the FM broadcast with the de-emphasis characteristic of 50 μsec is received, if the FM broadcast is heard within the reception area of the FM inter-station frequency of 200 KHz with the de-emphasis characteristic as it is, only the high-pitched sound will be coordinated, 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.

Therefore, the present invention has solved such a conventional problem, and provides a receiver having a synthesizer tuner capable of changing the inter-station frequency or the de-emphasis characteristic without adding a key such as a manual switch. It is a proposal.

[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 is provided to select the broadcasting station to be received, and a specific key among them is also used as a key for changing the frequency between stations or the de-emphasis characteristic. , The inter-station frequency to be swept or the de-emphasis characteristic is set to a different value when the first key of the dual-purpose keys is operated for a predetermined time or more and when the second key is operated for a predetermined time or more. It is characterized by being done in this way.

[Operation] The function to be set is the inter-station frequency or de-emphasis characteristics. 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 a specific key provided in the tuning operation unit is operated.
Therefore, of the keys provided on the tuning operation unit, a specific key functions as a dual-purpose key.

That is, in this example, the preset key P ₀ is used as the first combined key, and when the preset key P ₀ is operated for a predetermined time, for example, 5 seconds or more, processing other than the preset processing is executed. In this example, when it is operated for a predetermined time or more,
AM inter-station frequency is 10KHz, FM de-emphasis characteristic is 7
It is set to 5 μsec respectively.

On the other hand, when the preset key P1 that functions as the second combined key is operated for a predetermined time (5 seconds) or more, this time, the AM inter-station frequency is set to 9 KHz and the FM de-emphasis characteristic is set to 50 μsec. To be done.

This allows the modification process described above to be accomplished by making good use of existing keys.

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 detection output is supplied to the low frequency amplifier 5 after its frequency characteristic is limited by the FM 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. The blogable value is 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.

FM de-emphasis circuit 90 provided in the FM receiver 70
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 broadcasting in the United States, etc., the time constant of the FM de-emphasis circuit 90 must be changed to 75 μsec, which is larger than that in Japan. In that case, the control signal causes the control transistor Q to change. It is controlled to the ON state. By doing this, capacitors C1 and C2
Are connected in parallel, the time constant becomes large.

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 a specific key is operated for a predetermined time or more is built in.

The predetermined time means a time that is not operated in a normal processing operation, and in this example, 5 seconds is set as the predetermined time.

In this example, two preset keys P ₀ and P1 among the keys provided on the tuning operation unit 35 as shown in FIG. 3 are used as specific keys. Of these, the preset key P ₀ is used as the first combined key, and the preset key
P1 is used as the second combined key.

In the embodiment, when the first combination key P ₀ is operated, the inter-station frequency is set to 10 KHz and the FM de-emphasis characteristic is set to 75 μsec. On the other hand, when the second combined key P1 is operated, the inter-station frequency becomes 9 KHz and the FM
The de-emphasis characteristic is set to 50 μsec.

In FIG. 3, M is a memory key, U is an up key for frequency up, and D is a down key.

Now, setting the frequency between stations and FM de-emphasis circuit
The constant change processing of 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, and the reception band and the dual-purpose keys P ₀ , P
When the initialization 1 is set and the power is turned on, the same processing as when the first combination key P ₀ is operated is executed. That is, the de-emphasis characteristic is automatically set to 75 μsec and the AM inter-station frequency is set to 10 KHz (steps 41 to 43).

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 initial setting 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 read from the key operation unit (not shown) of the apparatus body and the tuning operation unit 35 (step 44). ).

Thereafter, among the preset keys P, the operation states of the dual-purpose keys P ₀ and P 1 are checked, and when none of them is operated, the operation state of the memory key M shown in FIG. 3 is checked (steps 45 to 45). 47).

When the memory key M is not operated and another key is operated, a series of processes (broadcast station reception process, etc.) corresponding to it is performed (step 48).

When the memory key M is operated, a transition is made to the channel preset mode (step 49). That is,
When the memory key M is operated, at least either the channel selection mode or the channel preset mode processing is performed.

Now, when the second combination key P1 is operated after the key is read, the preset content (preset channel frequency) corresponding to this combination key P1 is read out and the channel is displayed and the channel is selected. (Step 51).

However, when the operation time of the second dual-purpose key P1 exceeds a predetermined time, the de-emphasis characteristic is changed to 50 μsec and the AM inter-station frequency is changed to 9 KHz instead of the preset content processing. (Step 4
6,51-54).

On the other hand, when it is determined that the first combination key P ₀ is operated for 5 seconds or longer, the FM de-emphasis characteristic is changed to 75 μsec and the AM inter-station frequency is 10K.
Is changed to Hz (steps 45, 55, 56, 42, 43).

However, in this example, since the change of the FM de-emphasis characteristic and the AM inter-station frequency at the time of operating the dual-purpose key P ₀ has 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 combined key P ₀
When is operated, the frequency between FM stations is set to 200KHz. In the case of the second combined key P1, the inter-station frequency is set to 100 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.

[Effect of the Invention] As described above, according to the configuration of the present invention, a specific key among the keys provided in the tuning operation unit is also used as a key for changing the inter-station frequency or the de-emphasis characteristic, When the dual-purpose key is operated, it is possible to realize a specific changing process (such as changing process between stations) accompanying the specified key operation.

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 preset 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 P ₀ …… 1st combined key P 1 …… 2nd combined key

Claims (1)

[Claims] 1. A tuning operation section composed of a plurality of keys is provided for selecting a broadcasting station to be received, and the key is also used as a key for changing an inter-station frequency or a de-emphasis characteristic. At the same time, the inter-station frequency to be swept or the de-emphasis characteristic is set to a different value when the first key of the dual-purpose keys is operated for a predetermined time or longer and when the second key is operated for a predetermined time or more. And a receiver having a synthesizer tuner.