JPS631476Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention is particularly useful for wireless communication equipment, etc., and is capable of pitch control, and even when the passband is changed, the setting position of the notch filter can be set independently without changing. It's about machines. Recent receivers have excellent interference removal functions, and for example, as shown in the block diagram of a conventional receiver shown in Fig. 1, the passband can be adjusted arbitrarily.
Moreover, it can change continuously and also has a notch filter function.

In the figure, 1, 2, 4 are mixers, 1F, 2F are IF amplifiers, 1C and 2C are local oscillators, N is a notch filter, NC is a notch filter control section, PL is a PLL oscillator for varying the receiving frequency, and D is a detection section , A is a low frequency amplifier, SP is a speaker, AN is an antenna, 1C and 2C are local oscillators for adjusting the passband width, and the passband width can be continuously adjusted by changing the oscillation frequency of each. Moreover, it can be changed arbitrarily.

By configuring as described above, it was possible to provide an interference removal function that was not available in the past, but it still has the following drawbacks. In other words, changing the passband due to the circuit configuration will also change the output frequency of mixer 2, which will cause the same result as changing the notch filter control section NC, and the setting position of the notch filter N will shift. It happens. Therefore, it is necessary to first set the above-mentioned pass band width and then adjust the notch filter, which may result in a fixed and complicated operation order. FIG. 2 is a block diagram of a receiver that we have previously developed, and in addition to the circuit configuration shown in FIG. 1, it includes mixers 3 and 5, an IF amplifier 3F, and a local oscillator 3C. In this circuit, because of the additional configuration described above, when the oscillation frequency of the local oscillators 1C and 2C is changed to vary the passband width, the setting position of the notch filter N will not shift as in the case of Fig. 1. do not have.

However, even in the circuit shown in Figure 2, CW
Since pitch control cannot be performed during reception, the PLL oscillator PL is intentionally shifted and the band is readjusted to change the pitch. However, this will cause a frequency shift and is not the original usage.

The purpose of the present invention is to solve the above-mentioned difficulties, to perform pitch control without making major changes to the conventional configuration, and to prevent the setting position of the notch filter from changing even when the passband width is changed. It is an object of the present invention to provide a receiver that can be set independently without any trouble and is easy to operate.

Hereinafter, an embodiment of the present invention will be described based on FIG.

This invention basically utilizes the circuit configuration that we developed earlier, as shown in Figure 2.
In addition to the circuit configuration shown in the figure, mixer 6, IF amplifier 4
F, a fixed local oscillator 4C, a switch S1 as a switching means, and a pitch control oscillator PC. The pitch control oscillator PC is
The oscillation frequency is configured to be variable around the fixed oscillation frequency of the local oscillator 3C. The outputs of the local oscillator 3C and the pitch control oscillator PC are selectively input to the detection section D by switching the switch S1.

In FIG. 3, by first switching the switch S1 to the a side and performing CW reception, it is possible to tune to the frequency of the other station with zero beats.

Next, when the switch S1 is switched to the b side to perform CW reception, the difference between the oscillation frequency of the local oscillator 3C and the oscillation frequency of the pitch control oscillator PC becomes a beat sound and is emitted from the speaker SP.
At this time, by varying the oscillation frequency of the pitch control oscillator PC, the pitch of the beat sound can be changed without changing the reception frequency.

Therefore, in the circuit shown in Figure 3, even if the band is varied by changing the local oscillators 1C and 2C as in Figure 2, the notch filter setting position will not shift, and furthermore, the receiving frequency will not change. The pitch of CW reception can be varied without any problem.

As described above, according to the receiver according to the present invention, not only can the bandwidth be arbitrarily varied, but also the notch filter adjustment and pitch control can be performed independently. There is no impact at all.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional receiver, Figure 2 is a basic block diagram of a receiver that we developed earlier,
FIG. 3 is a block diagram showing an embodiment of the receiver according to the present invention. 1C, 2C, 3C, 4C...Local oscillator, PL
...PLL oscillator, 1, 2, 3, 4, 5...Mixer, 1F, 2F, 3F, 4F...IF amplifier, N
...Notchi filter, NC...Notchi filter control section, PC...Pitch control oscillator, S
1...Switch.

Claims (1)

[Scope of utility model registration request] The receiver is equipped with first and second variable frequency local oscillators and a notch filter for obtaining an arbitrary passband width, and includes a control unit dedicated to setting the notch filter, a fixed local oscillator, and a pitch control unit for CW reception. It consists of a third variable local oscillator for continuously varying the height, and a switching means for selectively connecting the output of the fixed local oscillator and the output of the third local oscillator to the detection stage. 1. A receiver characterized in that a bandwidth, a notch filter, and a pitch height during CW reception can be independently set.