Providing space saving of two-way conversation devices by integrating power amplifier and voice switch

August 31, 2009

New Japan Radio releases the NJW1128,
Voice Switch for Door Intercom with Power Amplifier

August 31, 2009 - New Japan Radio Co., Ltd. has introduced to the market, the NJW1128, a voice switch with power amplifier, suitable for applications of two-way conversation devices such as door intercom, interphone, hot-water supply system remote controller with call function and conference systems.

[Background of development]

The NJW1124(march 17, 2008 released), provides miniaturization and high-reliability of two-way conversation devices by integrating all of its functions, that are realized by discrete circuits conventionally, into one chip. But it needs a power amplifier as an external part. The NJW1128 includes the power amplifier, for downsizing of circuit board in two-way conversation devices.

[Features]

The NJW 1128 consists of a power amplifier, receiver amplifier, line amplifier, microphone amplifier, sending/receiving attenuator, level detector and noise detection circuit (background noise monitor). In two-way conversation devices that have a speaker and a microphone close to each other, sound from the speaker is picked up and amplified by microphone and reproduced by the speaker in a circle. This causes howling and echo. The NJW1128, however, prevents these problems, determining which side has priority by judging volume of input signal, increasing volume on the sender's side and decreasing volume of the receiver. Moreover, a noise detection circuit detects and reduces surrounding noise to keep conversation clear.

1.providing space saving of the board by built-in power amplifier
The NJW1128 provides space saving of the board by built-in power amplifier that is external part in the NJW1124.
2.Capable of making all external condensers by ceramic condensers
Conventional voice switches have required an electrolytic capacitor, but the NJW1128 helps to improve reliability, lower cost and extend operating life because it is compatible with ceramic condensers.
3.Built-in press-to-talk (forced sending/receiving) function to talk whenever desired and mode monitoring port
It has two important functions inside that are realized by discrete circuits conventionally, one is press-to-talk function, and the other is mode monitoring port.
Product Name NJW1128
Function Voice Switch for Door Intercom with Power Amplifier
Applications Door intercom/Interphone,
Water heater remote controller with call function Conference system,
Radio equipment, Guard system
Packaging LQFP48-R3 (9.0×9.0×1.5mm typ.)
NJW1128FR3

[Features & Characteristics]

[Schedule]

A detailed spec is here
NJW1128

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