LA7975 View Datasheet(PDF) - SANYO -> Panasonic

Part Name

Description

Manufacturer

LA7975

PAL SIF Converter Circuit for TV and VCR Multi-system

SANYO -> Panasonic 

LA7975

. Pin 5 is the output pin. The output from Pin 5 is input to the

SIF via a 6 MHz bandpass filter (BPF).

When 5.5 MHz is input to Pin 1, the spectrum shown in

Figure 10 is obtained at Pin 5. Even if there is a 5.85 MHz

NICAM signal, the D/U (desirable/undesirable) ratio at Pin 5

increases and the buzz characteristic does not deteriorate.

When 6 MHz is input at Pin 1 and there is a 6.552 MHz

NICAM signal, then 6.552 MHz is mixed with 500 kHz to

make 6.052 MHz. This becomes an interference signal and is

within the band for 6 MHz. Therefore,for 6 MHz input, Pin 4

is grounded with 10 kΩ to stop the oscillation and pass

through the input signal 6 MHz as is.

Figure 9

Output level

Unit (resistance: Ω)

Ceramic BPF

chracteristic

D/U ratio

Output level

Figure 10 (5.5 MHz input)

Interference obtained with LA7975 mixer

6.552 MHz – 500 kHz = 6.052 MHz

D/U

ratio

Figure 11 (6 MHz input)

Reference Characteristic Diagram

Input/output characteristic

VO – VCC

* S1 on for 6 MHz

measurement

Unit (resistance: Ω, capacitance: F)

Input level – dB/µV

* Input level 80 dB/µV S1 on

for 6 MHz measurement

Supply voltage, VCC – V

No.3994-5/6

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