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operates within the 900MHz ISM band. This equipment consists of a base
unit and a handset. The base unit is connected to a telephone network,
and has transmitter and receiver circuits which are served to
communication with the handset. The handset also has a transmitter and
receiver portions in addition to regular dialing circuit.)
(superscript: Both the handset and the base unit have PLL circuits which
enable to communicate in an empty channel. Pressing the CH key on the
handset can last the communications moving into other open channel
without cutting the line even if interfered by interruption on talks.)
(superscript: 1. Handset)
(superscript: 1) Local Frequencies and Intermediate Frequencies)
(superscript: TX VCO Frequency: 902.052464 MHz to 904.002470 MHz)
(superscript: RX 1st Local Freq.:
936.552559 MHz to 938.502564 MHz)
(superscript: RX VCO Frequency: 936.552559 MHz to 938.502564 MHz)
(superscript: RX 2nd Local Freq.:
10.100 MHz)
(superscript: 1st Intermediate Frequency: 10.555 MHz)
(superscript: 2nd Intermediate Frequency: 455 kHz)
(superscript: 2) Communication Link to Base unit)
(superscript: RX Circuit:)
(superscript: An incoming RF signal from the base unit is received
through the antenna. RX VCO frequency shown above is produced by PLL IC
(IC502) and RX VCO (IC502 1/2). Then, this frequency is the RX 1st Local
frequency.)
(superscript: This 1st local signal is applied to the 1st Mixer (IC502)
which produces 1st IF of 10.555MHz.)
(superscript: The 1st IF signal (10.555MHz) is mixed with 2nd local
frequency of 10.1MHz to produce the 2nd IF of 455kHz at IC401. AF signal
demodulated by IC401 is amplified by the audio amplifier
(Q401/Q403/Q405/Q406) to drive a speaker.)
(superscript: TX Circuit:)
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