Uniden Corporation

Uniden America Corporation

Tateo Masaki

Akira Ono

Hironori Warabi

Michio Toriya

Toshiharu Nakayama

A broadband receiver exhibiting reduced interference to a frequency counter caused by a local oscillator. The broadband receiver is arranged for detecting a radio signal of strong reception intensity and receiving the radio signal, and in a specific configuration includes: a reception system including an antenna for receiving the radio signal, a local oscillator for outputting a local oscillation signal, a frequency mixer for converting the radio signal to an intermediate frequency, and a demodulator for demodulating the intermediate frequency; a frequency counter for measuring the frequency of a radio signal having strong reception intensity; a control section for controlling the oscillation frequency of the local oscillator in such a manner that the radio signal having a strong reception intensity is demodulated by the reception system; and a local oscillator halting section for halting the oscillation of the local oscillator during the measurement of the frequency of the radio signal by the frequency counter.

Broadband receiver

A device for connecting an external sound generator having a plug and being incorporated in an apparatus having a circuit outputting an electrical sound signal. The external sound generator is, for instance, either one of a headphone having the plug of 3-pole stereophonic type or a earphone having the plug of 2-pole monophonic type. The device comprises a single jack having a first and second plus contacts and a minus contact for receiving the electrical sound signal from the outputting circuit through the first plus contact and for supplying the electrical sound signal to the plug connected to the jack and an impedance element, such as a electric resistor, connected between the first and second plus contacts. The impedance element prevents a short circuit for use of an earphone having a 2-pole monophonic plug.

Device for connecting external sound generator

A controller shifts the frequency of the local oscillator with a frequency shift circuit so that as many channels to be scanned as possible will be included within specified bandwidths, detects a desired received signal by scanning each of the specified bandwidths with the shifted frequency, scans each channel within the bandwidth where the desired received signal was detected, and changes the frequency of the local oscillator or shifts the frequency of the local oscillator with the frequency shift circuit so that the desired channel frequency identified above will be at the center of said bandwidth.

Radio receiver with a high speed and accurate search operation and

A power supply switching apparatus for switching power supplies used to all electronic appliance such as a pager and a portable telephone is described. A battery pack includes a battery and is connectable to an external DC power supply. In the battery pack, a power supply connection detecting circuit detects whether or not the external DC power supply is connected to this battery pack, and a switching circuit switches the battery and the external DC power supply. In an appliance housing a voltage is detected by a voltage detecting circuit to judge whether the detected voltage corresponds to the voltage derived from the battery power supply, or the voltage derived from the external DC power supply, and another switching circuit switches the battery power supply and a power stabilizing circuit. Both of these battery pack and appliance housing constitute the power supply switching apparatus.

Power supply switching apparatus

In portable terminal units each of which has a rechargeable battery and a data processing section, one terminal is used as both a terminal for charging the rechargeable battery and a terminal for connecting a data processing unit to an external data processing unit. First protective circuitry protects the data processing unit from a battery charging current and second protective circuitry eliminates loading of the rechargeable battery due to a data voltage and protects the external data processing unit from charging current for the chargeable battery.

Portable terminal unit with a dual purpose external connection

A method of searching a specified band of frequencies for a plurality of active signal frequency in a scanning receiver is disclosed. In the preferred embodiment, a range of channel memory storage locations are specified and a controller in the scanning receiver repetitively scans the range of frequencies for active signal frequencies and stores a number corresponding to each active signal frequency in one of the storage locations. Upon filling all of the specified storage locations, the search and store operation is terminated.

Automatic frequency search and storage method

A highspeed scanning type radio receiver is disclosed which prevents an erroneous interruption of a scanning operation caused by high frequency noises produced from a clock oscillator and a local oscillator circuit employed therein. The highspeed scanning type radio receiver includes a highspeed clock oscillator, a lowspeed clock oscillator, and a clock switching circuit for switching these highspeed clock oscillator and lowspeed clock oscillator to be connected to a CPU. Normally, a searching operation is carried out by supplying the highspeed clock to the microcomputer. When a reception signal is detected in a certain channel, the highspeed clock is changed into the lowspeed clock to be supplied to the microcomputer, whereby a reception signal is again detected. When no reception signal is detectable, the microcomputer recognizes that the detection of the reception signal under operation at the highspeed clock is caused by high frequency noises, and commences a searching operation of the next channel.

Channel selecting method for radio receiver and highspeed scanning type

An automatic frequency transfer and storage method is disclosed in a scanning receiver having a channel memory having a plurality of storage locations for storing frequency numbers corresponding to frequencies. In the preferred embodiment, the storage locations are grouped into channel banks. Each storage location is identified with a channel number and each channel bank is identifed with a channel bank identifier. A source channel number and either a destination channel number or destination channel bank identifier are specified. A controller searches the specified channel bank for a clear storage location. In either case, the controller displays the pertinent frequency transfer information and the transfer is executed upon confirmation, and the source storage location is cleared.

Automatic frequency transfer and storage method

In a radio receiver for electronically selecting channels by way of the frequency synthesizer system, a highspeed channel scanning operation is realized. A CPU (central processing unit) detects both an SC (squelch control) signal derived from a squelch circuit and an output voltage from a frequency discriminator. The CPU controls data to be supplied to a PLL (phase-locked loop) circuit employed in a frequency synthesizer so as to perform a channel scanning operation scanning three channels concurrently. When the CPU judges that a desirable reception signal is detected based on a change in the SC signals during the concurrent scan operation. This CPU determines at which channel, the scanning operation is stopped among three channels: the central channel of the three channels searched during the concurrent scan operation, a channel higher in frequency than this searched channel by 1 step, and a channel lower in frequency than this searched channel by 1 step. Then, the CPU supplies PLL data corresponding to the channel at which the scanning operation is stopped into the PLL circuit employed in the frequency synthesizer.

Channel selecting method and highspeed scanning radio receiver which

Upon receipt of address data which matches one of a given plurality of capcodes, this pager executes a paging service corresponding to the matching capcode; this pager is characterized in that any capcode or capcodes specified as being invalid are replaced with a capcode or capcodes specified as being valid based on valid/invalid flags each corresponding to respective one of the capcodes.

Multi-capcode communication receiving equipment

An automatic tuning system in a high-speed scanning radio receiver provided with (a) a noise squelch circuit, first and second detecting circuits, first and second control circuits, a CPU circuit providing PLL data, and a scanning stop function. The squelch circuit generates a first (SP) signal when a decreasing trend in a noise detection voltage becomes lower than a preset reference voltage. The first detecting circuit judges whether or not the SP signal is generated within first predetermined time period (M1). The first control circuit causes the second detecting circuit to detect whether or not the SC signal is generated within a second predetermined time period (M2; M2&gt;M1) when the first detecting circuit detects the SP signal has been generated, and the second control circuit causes the second detecting circuit to detect whether or not the SC signal is generated within a third predetermined time period (M3; M3&gt;M1) when the first detecting circuit detects the SP signal for the current channel being scanned has not been generated and the SP signal for the preceeding scanning was generated. Accordingly, even if no SP signal for the current channel being scanned has been detected, the system is capable of securely detecting the SC signal by extending a SC signal monitoring period to the period M3, and thus securely stopping searching whenever the SC signal is generated.

Growing community of inventors

Sakura, Japan

Tateo Masaki