Kenwood YK-88C, PS-50, SP-430, PS-430, MB-430, AT-440 Usb, Lsb, Fs K, Am, Fm, Displayed frequencie s

TS-440S

CIRCUIT DESCRIPTION

I=1800, J=7244, K=19800, L=3239, M=4 1
fin = 0 .388 fsTD	1 1

When fIN = 30 MHz (USB mode) in formula 10 , f IN an d fSTD have the following relationship :

I = 1800, J = 7244, K = 19800, L = 3239, M = 7 3
.' . fIN = 0 .833 fSTD	1 2

Since the precision of the reference crystal oscillator use d in the TS-440 is 10 ppm (—10 to 50°C) and the receive r system has the characteristics shown in items i) and ii), th e total accuracy is stable at any point from 30 kHz to 30 MHz . The maximum amount of frequency shift is only +/— 30 0 Hz (see formula 12 ) . The characteristic shown in ite m

iii)enables variable band functions such as IF shift to be im - plemented, using the microprocessor . The microprocesso r also is used to set carrier points by adjusting fcAR, and to se t and adjust the amount of IF shift .

So far received frequencies in the SSB mode have been dis -

cussed . For receive modes other than SSB, and in transmit mode, operating frequency is determined by the referenc e frequency and frequency division data .

In CW receive mode, fvco is shifted down 800 Hz and used as fvco3 . In AM or FM receive mode, fCAR generation i s stopped . In FM receive mode, fHET is modulated by addin g audio signals to VCO5 from the microphone . FSK (RTTY) i s transmitted in LSB mode and uses AFSK by adding audio sig - nals externally .

The type of frequency displayed differs, depending on th e mode, as shown in Table 1 .

Mode	Displayed frequenc y
USB, LSB, FS K	Carrier point frequency
CW	Transmission carrier frequenc y
AM, FM	IF filter center frequency

Table 1 Displayed frequencie s

3 . Receiver Circuit Description

	CF I	Q7, 8	IC 7
		3SK73GRx2
			µPC2002V
				S P
SSB	C .F		AF P A

CF 2

C . F

IC 2

C335 7

f I F AMP . DE T Noise S O

CF 3

CFW455

Fig . 3 Receiver circuit configuratio n

6